To purchase this Sefer, click here
A. The obligation:
On Rosh Chodesh one recites the abridged Hallel [i.e. half Hallel]. This applies for both a congregation and a person who is praying in private. The paragraphs of Lo Lanu and Ahavti are skipped.
Are women obligated to recite Hallel?
Women are exempt from reciting Hallel. Nevertheless, they are permitted to recite it if they so choose. Regarding if women are to say a blessing-see the next Halacha!
May one recite Hallel during the year on a non-Holiday?
It is forbidden to recite Hallel during the year for the sake of reading the Hallel Song, at a time that is not obligatory. This possibly applies even if one is saying it without a blessing. It is however permitted to recite the Psalms of Hallel that are contained within Tehillim, if one is not doing so for the sake of reading Hallel.
May one recite Hallel twice on Rosh Chodesh?
No. This applies even if one reads the Hallel without a blessing. It is however permitted to read Hallel as part of the Psalms in Tehillim.
What is one to do if he accidently began to say the paragraph of Lo Lanu or Ahavti?
He is to conclude the verse in which he is holding and then continue with the next paragraph.
Sparks of Chassidus
Why we say Hallel on Rosh Chodesh:
The saying of Hallel is not just mere lip service but actually affects the world’s reception of Divine light. The prayer of Hallel is meant to draw down levels of above nature into the natural order of the world. Now, the weekday is meant to follow the natural order of the world and therefore is not fit for the recital of Hallel which represents miracle and above nature. Therefore, not only do we not recite Hallel during the week, but it is even forbidden according to Halacha, as stated above. On Shabbos, Hallel is likewise not recited being that Shabbos follows the order of above nature, and hence has no need for the above nature effects of Hallel. Rosh Chodesh however is a day in which work is optional, and thus, while not following the natural order of the world which requires one to work, is also not on the level of Shabbos. It is on this day that we say Hallel to draw down the light of above nature into nature.
B. The blessing over Hallel:
Some Poskim rule that whenever half Hallel is recited, it is to be said without saying a blessing before or after [even when Davening with a Minyan, and even the Chazan is not to say a blessing]. Other Poskim however rule that if the Hallel is being recited with a Minyan then a before and after blessing is to be recited, however an individual [praying without a Minyan] does not recite either blessing. Other Poskim however rule that every individual may recite a blessing even if he is not partaking in a Minyan. Practically the custom [of Sefaradim] in Eretz Yisrael and the surrounding cities is not to recite a blessing even in a Minyan. However the Ashkenazi custom is that every person recites a blessing even if he is Davening in private, without a Minyan. Nevertheless, one is to beware to try to recite Hallel with the Minyan. Furthermore, when reciting Hallel with the Minyan, only the Chazan is to recite the before and after blessing and he is to have in mind for the congregation to fulfill their obligation with him. In turn, the congregation is to answer Amen and fulfill their obligation with his blessing. [However if one is praying privately he is to recite the opening and concluding blessings of Hallel even when the entire Hallel is not recited and so is the Chabad custom. Furthermore many Chabad Chassidim are accustomed to recite the blessing on their own even when Davening with the Minyan. Some recite it prior to the Chazan and hence complete it prior to the Chazan completing his blessing. Others recite it together with the Chazan and some recite it after the Chazan.]
One is to recite a before and after blessing over Hallel on Rosh Chodesh. If one is saying Hallel with the Minyan one is to be Yotzei with the Chazan’s blessing, although many are accustomed to say the blessing to themselves even in such a case.
Are women who recite Hallel to recite a blessing before and after?
Some Poskim rule that women are not to recite a blessing upon reciting Hallel. This applies even towards those women of Ashkenazi origin that usually recite a blessing prior to performing their optional Mitzvos. Other Poskim however rule that women may recite the blessing and so is the widespread custom.
Why is the blessing of Shehechiyanu not recited over Hallel?
As in order to recite Shehechiyanu on a Mitzvah that comes on occasion there must be a break of 30 days between the current and previous Mitzvah, and since at times there is only 29 days in between the two Rosh Chodesh therefore Shehechiyanu is not recited.
What is the law if one accidently recited the blessing of Ligmor Es Hallel?
He fulfills his obligation and is not required to repeat the blessing.
If a Sefaradi is a Chazan by an Ashkenazi Minyan, may he say a blessing over the Hallel on behalf of the congregation?
C. When is Hallel to be recited?
From when during the day, and until when in the day: Hallel may be recited throughout the entire day, from dawn [Alos Hashachar] until nightfall [Tzeis Hakochavim]. Thus, if one did not recite Hallel immediately after Davening [Shemoneh Esrei of] Shacharis, he may recite it throughout the day, until Tzeis Hakochavim.
May one initially read Hallel before sunrise? Lechatchilah one should not recite Hallel prior to sunrise. Nevertheless, if one transgressed and recited Hallel prior to sunrise, after daybreak he has fulfilled his obligation.
After Shemoneh Esrei: Although Hallel may be recited throughout the day, it is best to recite it immediately after the Shacharis Shemoneh Esrei. [It is permitted to recite Hallel prior to Davening Shacharis. Nevertheless, according to the Arizal, Hallel is not to be said prior to Davening.]
May Hallel be recited with a blessing after sunset, prior to nightfall?
No. One is to recite Hallel without a blessing.
May one eat before Hallel?
One is to avoid eating prior to reciting Hallel, unless he is sick or weak in which case he is not to be stringent even as an act of piety. [Thus, even if one already Davened Shacharis but has not yet recited Hallel, he should avoid eating until he recites Hallel.]
D. Reading Hallel with the congregation:
It is a Mitzvah Min Hamuvchar to read Hallel together with the congregation immediately after [Shemoneh Esrei of] the Shacharis prayer.
Reading Hallel with the congregation prior to Shacharis? If one came to Shul after the congregation completed the Shacharis prayer [of Shemoneh Esrei] and has reached the saying of Hallel, and has not yet Davened Shacharis, then there is an opinion that says that if there is no worry that the time of Shema will pass, it is best for him to first recite Hallel with the congregation, and afterwards Daven Shacharis. This applies even on those days that one who Davens without a Minyan recites the complete Hallel with a blessing according to all opinions. [Nevertheless, the Arizal was not comfortable with such an arrangement of reciting Hallel out of its proper order, and hence according to the Arizal one is never to read Hallel prior to Davening. Practically, the widespread custom amongst Chabad Chassidim is not to recite Hallel before Davening, as explained in the summary below.]
If one is in the middle of Davening: If one is holding in middle of Davening, past Baruch Sheamar, at the time that the congregation begins to read Hallel, he is not to make an interval in order to read Hallel together with them. [However this only applies] on those days [i.e. all of Sukkos and Chanukah; 2 days of Pesach] that even one who is Davening without a Minyan recites the complete Hallel with a blessing. [However on those days that the Hallel is recited without a blessing when one is praying without a Minyan [i.e. Rosh Chodesh and Chol Hamoed Pesach], then one is to stop and recite the Hallel together with the congregation. He is however not to recite a blessing prior to the Hallel and is rather to fulfill his obligation with the blessing recited by the Chazan. If one has already completed Pesukei Dezimra then he may no longer make an interval to recite Hallel with the congregation, even on days that one reads the incomplete Hallel.]
One is to be particular to read Hallel together with the congregation immediately after Shemoneh Esrei. If one is holding prior to Davening, some Poskim rule he is to stop and recite Hallel together with the congregation. This applies for Hallel of all days. If one is holding within Pesukei Dezimra, then some Poskim rule by half Hallel [of Rosh Chodesh and Chol Hamoed Pesach] he is to stop and recite Hallel together with the congregation. Nevertheless, the Arizal was not comfortable with such an arrangement of reciting Hallel out of its proper order, and hence according to the Arizal one is never to read Hallel prior to Davening.
The Chabad Custom:
No clear directive has been given with regards to the Chabad custom in whether one should say Hallel with the congregation prior to his Davening, if the circumstance occurs. Nevertheless, it is known that the Chabad Rabbeim would be careful to always pray with the same pace as the Minyan on Yom Tov in order to say Hallel with the congregation. This is despite the Rabbeim’s usual practice of praying at greater length than the Minyan. [Practically, the widespread custom amongst Chabad Chassidim is not to recite it before Davening.]
Should one who usually Davens in great length without the congregation do so on days that Hallel is said?
The Rebbe Rashab would Daven Shacharis of Yom Tov on pace of congregation in order to say Hallel with the congregation after Shacharis, at its appropriate time. [Seemingly, this would apply likewise on Rosh Chodesh.]
E. Being Yotzei Hallel by hearing it from another person/Fulfilling one’s obligation with the Chazan:
One can fulfill his obligation of Hallel through hearing it recited from another person. One can thus fulfill his obligation of Hallel through hearing the reading of the Chazan. [In such a case, he is required to hear the entire recital of Hallel from the Chazan.] This applies even if a Minyan is not present. This applies even if the person reciting Hallel has already fulfilled his obligation of Hallel. Nevertheless, this only applies if the listener answers “Halleluka” for each stanza recited. If he does not answer Hallelukah after each stanza, and is expert in how to do so, then he does not fulfill his obligation. However, some Poskim are lenient in a case that the person reciting the Hallel has not yet fulfilled his obligation, in which case it is not required for the listeners to recite Halleluka, even if they know how to do so. If the listener does not know how to recite the Hallelukah then he fulfills his obligation even if he does not answer Halleluka.
Hearing from many people reading simultaneously: It is permitted for many people to read the Hallel aloud simultaneously and have the remainder of the congregation listen and fulfill their obligation through this hearing. [One thus fulfills his obligation of Hallel through hearing the Chazan recite it even if there are other people saying Hallel aloud simultaneously.]
One fulfills his obligation of Hallel through hearing it recited from another person, even if a Minyan is not present and the person reciting it has already fulfilled his obligation. [Practically, those that are not expert in answering the Halleluka’s for the stanzas fulfill their obligation even if they do not do so.]
May a woman read Hallel on behalf of a man for him to fulfill his obligation?
No. If however the man repeats each word after her then he fulfills his obligation. Nevertheless, one who succumbs to this will have a curse befall upon his home. However, some Poskim rule that the above only applies to the complete Hallel recited on Holidays and Chanukah. However, on Rosh Chodesh, possibly a woman who is accustomed to say Hallel may read on behalf of a man who is listening and have him fulfill his obligation.
May a child read Hallel on behalf of another?
One does not fulfill his obligation with hearing the reading of Hallel from a child below the age of Bar Mitzvah even if he has reached the age of Chinuch. [However, it is possible that the above only applies to the complete Hallel recited on Holidays and Chanukah, while on Rosh Chodesh, perhaps a child may read on behalf of a man who is listening and have him fulfill his obligation. Practically, one is to be stringent in this matter.]
F. The Nussach:
The language: From the letter of the law, Hallel may be recited in any language. One fulfills his obligation even if he does not understand the language that he is reading. [Nevertheless, it is a Mitzvah Min Hamuvchar to recite Hallel in Lashon Hakodesh.]
Which verses in Hallel are to be repeated? There are different customs regarding which verses are said twice. Each community is to follow their custom. [The widespread custom is to repeat each verse from Odecha until the conclusion of Hallel, by the verse of Hodu Lahashem. This is likewise the Chabad custom.]
Which parts are to be read aloud by the Chazan and repeated by the congregation? There are different customs regarding which verses are said aloud by the Chazan and then repeated by the congregation. Each community is to follow their custom. [The Chabad custom is for the Chazan to recite Hodu and for the listeners to recite Hodu and Yomar Nah. The Chazan repeats the verse of Hodu together with the congregation. The Chazan then recites Yomar and the listeners answer Hodu and Yomru Nah Beis. The Chazan then recites Yomru Nah Beis and the listeners answer Hodu and Yomru Nah Yirei. The Chazan then recites Yomru Nah Yirei and the listeners answer Hodu. The four phrases beginning Ana Hashem are each recited by the Chazan and repeated by the congregation. The stanzas are to be recited clearly by the Chazan and then answered by the congregation. Hence, the singing that customarily takes place during this recital should not drown out the voice of the Chazan or the congregation.]
One who is praying without a Minyan: The verse beginning Hodu LaHashem is repeated after each of the next three verses, even when one is praying in private.
Saying Hodu with two other people when praying privately: If one is reciting Hallel without a Minyan it is a Mitzvah to have another two people listen and answer [for Hodu and Ana]. This applies on all days that Hallel is recited, whether the complete or incomplete Hallel. [If however one cannot find another two people easily, then he is not required to trouble himself any further. Even one’s wife, and children that have reached Chinuch, join to make up the other two people needed for this purpose. However, it is a Mitzvah Min Hamuvchar to say it with two other men that are above the age of Mitzvos. Even if one has already recited Hallel he can join to answer for Hallel.]
The word Al in the concluding paragraph: In the concluding paragraph the word “al” should be omitted.
Avraham Zakein: Some are accustomed to recite on Rosh Chodesh after Hallel the verse beginning Veavraham Zakein and Zevadya Yishmereini. All this [including Avraham Zakein] is recited a total of three times. This is the Chabad custom. One is to say Avraham Zakein and Zevadaya Yishmereini together three times, and not first Avraham Zakein three times and then Zevadya three times.
G. Hefsek-Making an interval to answer Amen and the like:
Complete Hallel: When the complete Hallel is recited, the laws of making a Hefsek [speech interval] during Hallel has the same laws as a Hefsek during the reading of the morning Shema. This applies for both the laws of Hefsek within individual paragraphs and between paragraphs.
Half Hallel: When the half Hallel is recited, such as on Rosh Chodesh and Chol Hamoed Pesach, then it has the same laws of interval of between paragraphs. [Some learn this to mean that it has the same status as between the paragraphs of Shema. Others learn this to mean that it has the same status as Pesukei Dezimra. Practically, one may stop to answer everything that one can answer during Shema, which includes: Amen Yihei Shimei Raba and Amen of Daamiran Bealma of Kaddish; Kadosh Kadosh, Baruch and Yimloch of Kedusha; Borchu; The three words of Modim Anachnu Lach; Amen for Birchas Hatorah, Hakeil Hakadosh and Shomeia Tefila. One may make an interval even in the midst of a verse, although in the event that one did so he is to return to the beginning of that verse.]
H. Making a long interval in middle of Hallel:
- Example: One went to the bathroom in middle of Hallel and remained there for five to ten minutes. Must he repeat Hallel from the beginning?
If one made an interval during Hallel, even if the interval was as long as the amount of time it would take to read the entire Hallel, he may nevertheless continue from where he had left off. This applies even if one made an interval due to a [Halachic] Oness, such as one entered a bathroom, which is a place that Hallel cannot be recited. Nevertheless, some Poskim are stringent [regarding days that the complete Hallel is recited], to require one to repeat from the beginning of Hallel, if one made a long interval due to Oness. Practically, one is to be stringent like their opinion [on days of complete Hallel] to repeat from the start of Hallel, although the blessing is not to be repeated. This however only applies if one had a Halachic Oness, which refers to one who made an interval in the reading due to a Halachic prohibition to continue the reading, such as if the reader had to use the bathroom in middle. In any other type of Oness the reader fulfills his obligation.
I. Standing for Hallel:
Hallel is to be recited while standing.
Leaning: It is forbidden for one to lean on any item during Hallel [in a way that it supports him from falling].
Transgressed: If one transgressed and recited Hallel in a sitting position he nevertheless fulfills his obligation and is not required to repeat the recital of Hallel.
J. Reading Hallel in the wrong order and skipping a verse:
One who reads Hallel in the wrong order does not fulfill his obligation. This applies to one who reads the verses within a paragraph in the wrong order. If however the verses in each paragraph were read in the correct order, although the paragraphs themselves were not read in order, then some Poskim rule it is valid Bedieved, even though that initially one may not do so. Other Poskim however rule it is invalid even in such a case.
Repeating if read in wrong order: In the event that one read Hallel in the wrong order, he is to repeat it without a blessing. This applies whether one read the verses in the wrong order, or read the paragraphs in the wrong order.
Made a mistake-skipped verse: If one made a mistake [and continued the Hallel], then he is to return to the area of the mistake and repeat from there. Thus, if one skipped a verse and then remembered later on, he is not to recite the verse in the area that he remembered, but is rather to retract to that verse and continue from there. If he does not remember which verse he skipped then he is to return to the beginning of that paragraph.
If one skipped a verse or paragraph in Hallel does he fulfill his obligation?
Some Poskim rule that by the Hallel of Rosh Chodesh he fulfills his obligation.
K. Hallel in the house of a mourner:
The custom is to omit the saying of Hallel on Rosh Chodesh when praying in the house of a mourner. Nevertheless, after each member of the congregation returns home, they are obligated to recite Hallel.
Chanukah: During Chanukah, Hallel is recited in the house of the Avel just as it is recited in Shul.
Davening for the Amud on Chanukah: The custom is that a mourner, within 30 days of other relatives and within 12 months of a parent, does not lead the Hallel prayer for the congregation.
Sparks of Chassidus
The meaning and effect of Hallel:
The term Hallel means praise. This has one of two meanings. 1) That we thank and praise G-d for the great joy and for the revelations given to us from above. 2) That we draw down a revelation below. There is no contradiction between the two explanations, and rather it means that by us praising G-d we cause the great revelation of G-dliness below, which is the source of our joy.
 Michaber 422/2
Obligation or custom: The recital of Hallel on Rosh Chodesh is not required from the letter of the law. [See Erechin 10b; Levush 422/2 that only by a Chag is there an obligation] Nevertheless, it is the custom to recite it. [Admur 490/7; See Taanis 28b] Today, there is no man amongst Israel that does not read Hallel on Rosh Chodesh, Heaven Forefend. [Piskeiy Dinim 2/6]
Why does one recite Hallel on Rosh Chodesh? This custom is derived from the last Psalm in Tehillim 150 which mentions the word Hallelukah 12 times in correspondence to the 12 months. The last verse of Kol Haneshamah is repeated in correspondence to the 13th month of a leap year. [Shivlei Haleket in name of Geonim; Beis Yosef; Kaf Hachaim 422/22]
Why is there an abridged Hallel on Rosh Chodesh? Being that the recital of Hallel on Rosh Chodesh is only a custom, we therefore skip parts of it in order to emphasize its lack of obligation. [See 488/3; 490/7; Abudarham] Alternatively, the reason is because Rosh Chodesh is a day of atonement for children who would die of the Askara disease. The sacrifice of Rosh Chodesh would atone for them. Now, since this is a day of atonement and forgiveness just like Rosh Hashanah and Yom Kippur, therefore we do not recite the complete Hallel, just like Hallel is not recited on Rosh Hashanah. [Levush 422/3; Kaf Hachaim 422/23]
Opinion of Rambam: The Rambam [Chanukah 3/7] rules that the abridged Hallel was only established to be recited by a congregation, while an individual is not to recite it. However, if he began to recite it then he is to complete it.
 Michaber ibid
 Siddur Admur; Tur 422; Elya Raba 422/12; Binyamin Zev 361; See Biur Halacha 422/6 “Lemafreia” based on Rambam Chanukah 3/8 that in truth one can skip which area he desires, however the above areas of skipping is the accepted custom.
 Admur 106/2; M”A 422/5; Mishnah Sukkah 38a; Tosafus Brachos 20b; Kaf Hachaim 422/28; See Admur in Kuntres Acharon 296/3
The reason: As it is a Rabbinical time dependent Mitzvah. [Admur ibid; M”A ibid]
 Kesher Gudal 23/7; Beis Oved 16
 M”A 422/5; Admur in Kuntres Acharon 296/3
 See Admur 584/1; M”A 584/1 regarding reciting the Psalms of Tehillim of Hallel on Rosh Hashanah that only those that say Tehillim on a daily basis and have reached the psalms of Hallel on a day that Hallel is not recited [as part of their regular cycle] are permitted to recite these psalms as usual. [However those that are not saying the Tehillim as part of any cycle may not specifically recite the psalms of Hallel in Tehillim.] Thus, the difference between Rosh Hashanah and a regular day is that on a regular day one may always choose to say the Psalms of Hallel for the sake of Tehillim, while on Rosh Hashanah even this is forbidden and it may only be said as part of one’s daily cycle.
 M”A ibid
 Rav A”C Naah in Yagdil Torah 4/1676
 The reason: As one may not say half of a verse. [ibid]
 Sichas Chayeh Sara Mevarchim Hachodesh Kisleiv 1951
 422/2; See glosses of Siddur of Rav Raskin for an overview in this matter
 Second opinion in Michaber ibid; Rashi; Rambam Brachos 11/16; Chanukah 3/7
 The reason: As Hallel on Rosh Chodesh is a mere custom and we do not recite a blessing over fulfilling a custom. [Kaf Hachaim 422/34]
 First opinion in Michaber ibid; Rif Shabbos 24b; Rabbeinu Yonah Brachos 14a
 Definition of a Minyan: In general a Minyan refers to ten adult men. However see Admur 479/6 that if one is reciting Hallel without a Minyan it is a Mitzvah to have another two people listen and answer [for Hodu and Ana]. In explanation of the reason behind this some opinions say that a Zimun of three is considered a congregation which warrants a blessing to be said, and hence in order to say a blessing according to all one should least strive to have at least three people. [Lechem Chamudos brought in M”A 422/7; M”B 422/18; Kaf Hachaim 422/39]
 May every individual recite the blessing or only the Chazan? It is implied from the wording of the Michaber and Rama that according to this opinion every person may recite the blessing when Hallel is being recited with the Minyan and it is not necessary for the Chazan to be Yotzei the congregation. Thus, when saying Hallel with the congregation everyone can say the blessing. [See Admur 619/8 “and so is the law regarding Hallel” that ideally due to Berov Am Hadras Melech it would be proper to have only the Chazan recite the blessing, however the custom became for everyone to say it] However, in the Siddur Admur rules that only the Chazan is to say the blessing [as will be explained at the end of this Halacha]. The Shaar Hakolel 37/4 explains that this is in order to suspect for the stringent opinion which states a blessing is never recited, and hence by half Hallel Admur rules that only the Chazan should recite it. See Glosses of Rav Raskin on Siddur footnote 8 that suggests that perhaps even according to this opinion only the Chazan is to say the blessing and not every individual.
 Opinion of Rama ibid; Rabbeinu Tam Taanis; Tosafus Erechin 10b; Tur in name of Rosh
 The reason: Although everyone agrees that the saying of Hallel on Rosh Chodesh is a custom, nevertheless it is permitted to recite a blessing over a custom just like women are accustomed to recite a blessing over the Mitzvah of Lulav, even though they are not obligated in the Mitzvah. [Tosafus Erechin ibid; Kaf Hachaim 422/36]
 Michaber ibid
 Rama 422/2
The reason: This is initially required in order to recite the blessing even according to the first opinion [i.e. second opinion brought above]. [Biur Hagra; Kaf Hachaim 422/37]
 Siddur Admur; Mishnas Chassidim based on Kabala; Siddur Rav Amram
Ruling of Siddur ibid: “On days that Half Hallel is recited it should be accustomed that the Chazan alone says the blessing at beginning and end while the congregation listens to the blessings, answers Amen and fulfills their obligation.”
The reason and other opinions: It is implied from the wording of the Michaber and Rama that [according to the second opinion] every person may recite the blessing when Hallel is being recited with the Minyan and it is not necessary for the Chazan to be Yotzei the congregation. In Admur 619/8 he rules that ideally due to Berov Am Hadras Melech it would be proper to have only the Chazan recite the blessing by all Mitzvos, such a Shehechiyanu, Lulav and Hallel, however the custom became for everyone to say the blessing themselves being that in most cases the Chazan does not have in mind to fulfill their obligation. However, in the Siddur Admur rules that only the Chazan is to say the blessing. The Shaar Hakolel 37/4 explains that this is in order to suspect for the stringent opinion which states a blessing is never recited, and hence by half Hallel Admur rules that only the Chazan should recite it. See Glosses of Rav Raskin on Siddur footnote 8.
Reminding the Chazan: Many are accustomed to remind the Chazan before Hallel to have the congregation in mind within his blessing. [Shaar Hakolel 37/4]
 Siddur Admur; Regarding why Admur here directs the congregation to answer Amen: See Likkut Dinei Rosh Chodesh 7 footnote 9; Admur 215; 594/1; M”B 213/17
 Implication of Rama ibid; Tanya Rabasi 32; Hamanhig brought in Shaar Hakolel 37/5
 Sefer Haminhagim p. 69 [English]; Hayom Yom 1st Teves; Igros Kodesh 18/84 [printed in Shulchan Menachem 2/200]; Shaar Hakolel 37/5; Custom of Tzemach Tzedek [as brought in Shaar Hakolel ibid; however see Kuntres Piskei Hasiddur]; Reshimos 8/20 that the Rebbe Rashab always said the blessing to himself even with a Minyan however he stated not to publicize this matter to others; See glosses of Siddur of Rav Raskin p. 475 for an overview in this matter
Ruling of Admur in Siddur and overview of Chabad custom: In the Siddur of Admur he does not write the law regarding an individual reciting Hallel and only writes regarding saying the blessing in a Minyan. The Shaar Hakolel 37/5 learns that Admur did not rule for us in this regard and hence one is to follow the ruling of the Rama that in our communities the custom is to recite the blessing. So was also heard to be the custom of the Tzemach Tzedek. Those Siddurim of Admur which state that a Yachid is not to say the blessing are inaccurate, as Admur never wrote these words and it was added by the publishers. Thus one is not to break from the accepted custom of the Rama. [Shaar Hakolel ibid] However see Glossses of the Rebbe Rashab on the Siddur who wrote that he asked his father the Rebbe Maharash about this issue and he replied that the Tzemach Tzedek told him that what was written in the Siddur by the publishers was most likely heard from the Maharil, and practically one can do as he chooses. Rav A”C Naah in Kuntres Piskeiy Hasiddur also concludes that the Tzemach Tzedek never gave a final ruling on this matter, and he thus argues on the conclusion of the Shaar Hakolel ibid. Practically, the Chabad custom as stated in Hayom Yom is to say it.
 Reshimos 8/20 that the Rebbe Rashab always said the blessing to himself even with a Minyan however he stated not to publicize this matter to others; Sichas Kodesh 1981 4/322 [brought in Shaareiy Halacha Uminhag 2/175; Shulchan Menachem 2/194] “It is customary of Chassidim to quietly grab the blessing of Half Hallel”; See glosses of Siddur of Rav Raskin for an overview in this matter; See also Likkut Dinei Rosh Chodesh 8 footnote 8; Heichal Baal Shem Tov 29/42
 As is the simple implication of the Rebbe’s words and as is the simple understanding of Admur in 619/8 that when saying the blessing of Hallel to oneself one is to say it prior to the Chazan and answer Amen to his blessing. See glosses of Siddur of Rav Raskin ibid; So rules also Yesod Veshoresh Havodah 12/4 regarding reading Megillah, that the listeners may answer Amen to the Chazan’s blessing even if they already said their own blessing beforehand.
 As finishing the blessing prior to the Chazan causes an issue of an interval as how can one answer Amen prior to beginning Hallel after his blessing. So rules Yalkut Yosef Moadim 5/295 regarding the above case of Megillah; See Panim Meiros 2/5; Shaareiy Teshuvah 167/11; See glosses of Siddur of Rav Raskin ibid
 Yeshuos Yaakov 422/6; Siddur Yaavetz; Kaf Hachaim 422/28 in name of Yeshuos Yaakov ibid
 Biur Halacha 422/2 “Hallel”
 Yeshuos Yaakov ibid; Biur Halacha ibid
 Abudarham Shaar 3; Kneses Hagedola 422; M”A 422/5; Kaf Hachaim 422/31
 Poskim in Kaf Hachaim 422/33
 Chaim Sheol 1/99; Kesher Gudal 23/5; Beis Oved 4; Kaf Hachaim 422/35
 Admur 488/3; Mishneh Megillah 20b
 Admur ibid; See also regarding Shofar: 588/1; Michaber 588/1
 The reason: As it appears like night in the eyes of the masses. [ibid] In 588/1 Admur writes as follows regarding Shofar: Biblically, day begins from Alos Hashachar regarding all Halachic matters. Nevertheless, the Sages decreed that one must delay blowing the Shofar until after sunrise being that not all people are expert in the definition of Alos and hence in order to be certain that it is day, one must wait until sunrise. [Admur ibid; Rashi Megillah ibid]
 Admur 131/5 in parentheses; See Rosh Hashanah 32b; Megillah 20b; 156/17
 The reason: As Zerizin Makdimim Lemitzvos. [ibid]
 See Admur 488/3, brought in next Halacha; Vetzrauch Iyun as to why even initially Hallel was not established to be recited prior to Shacharis. Perhaps the reason is because Hallel may only be recited after sunrise while one may Daven up until Shemoneh Esrei prior to sunrise.
 Shalmei Tzibur 223; Beis Oved 6; Kaf Hachaim 422/38
 Nitei Gavriel Chanukah 49/5; Regarding Shofar: Chayeh Adam 141/1; 144/20; Mishneh Berurah 588/1; Kaf Hachaim 588/2; 600/12; Regarding Lulav: M”A 658; Regarding Megillah: M”B 687/5; Kaf Hachaim 687/9; P”M 692 M”Z 3
Opinion of Admur: Admur ibid rules that from Alos until Tzeis is the permitted time for reciting Hallel. So writes Admur also regarding Shofar in 588/1 and 18/8 regarding Tzitzis. The source of Admur is from the Gemara Megillah 20b which states that until Tzeis Hakochavim it is considered day. This seems to imply that during Bein Hashmashos one may recite Hallel and blow Shofar even with a blessing! This is further inferred from the change of wording from the Tur 588 which writes simply “until night” while Admur specifies Tzeis. Vetzaruch Iyun Gadol, as Bein Hashmashos is questionable whether it is night or day as rules Admur is 261/1, hence how can one say a blessing at that time. Practically, the Poskim rule one is to not recite a blessing past sunset. Likewise, in the Siddur Admur retracted his ruling regarding Tzitzis, and rules the blessing may not be recited after sunset.
 Sheilas Yaavetz 40; Birkeiy Yosef 422/5; Shaareiy Teshuvah 422/5; Kaf Hachaim 422/30
 The reason: This is to be done in order so one be able to answer the prayer of Hodu and Ana together with the Chazan. [ibid] Alternativelyת it is done in order to be Yotzei the Bracha with the congregation
 Admur ibid
 Kol Bo; M”A 422/6; Mentioned in 131/5
 Shalmei Tzibur 223; Beis Oved 6; Kaf Hachaim 422/38
 Admur ibid
 This follows those opinions that say a blessing is not recited over Hallel on Rosh Chodesh unless it is recited with a Minyan.
 M”A 422/6; implication of Admur ibid
The reason: The saying of Hallel during Pesukei Dezimra is not considered an interval being that it consists of Psalms of praise which blend into the Pesukei Dezimra prayers. This is similar to the psalms added to Pesukei Dezimra on Shabbos and Yom Tov. [M”A ibid]
 M”A 422/6
The reason: As the blessing of before and after Hallel would be considered an interval between the blessings of Baruch Sheamar and Yishtabach which are already recited in Pesukei Dezimra. Thus, only on Rosh Chodesh and the like in which some Poskim rule a blessing is never recited is one to make an interval and read it without a blessing. [M”A ibid]
 Implication of M”A ibid that the allowance is only within Pesukei Dezimra
 Igros Kodesh 17/67 [See also Igros Kodesh 15/170; 18/81; see Shulchan Menachem 2/250; Shaar Halacha Uminhag 2/175]
 Hiskashrus 748; Rabbi Groner related in the name of the Rebbe, who said in the name of the Rebbe Rayatz, who said in the name of the Rebbe Rashab, that Hallel is not to be said outside of the order of Davening, as Davening Shemoneh Esrei without Hallel is like an old bread that has been baked a long time ago. [Hiskashrus 748]
 Igros Kodesh 17/67 [See also Igros Kodesh 15/170; 18/81; see Shulchan Menachem 2/250; Shaar Halacha Uminhag 2/175]
 See Admur 488/4; Sukkah 38; M”A 422/5; Biur Halacha 422/6 “Hallel”
The original Takana for reciting Hallel was for the leader of the congregation to recite Hallel aloud, and the congregation would listen quietly and answer Hallelukah after each stanza recited by the Chazan. [Rashi Sukkah 38a-b] There were a total of 123 Hallelukas said by the congregation. [Rambam Chanukah 3/12] In addition they would repeat the first verse of each paragraph after the Chazan [Roshei Perakim]. This custom gradually changed throughout the years, as is testified by the Gemara ibid 38b, in which those that knew how to recite Hallel would recite it on their own while those that did not would hear it from the Chazan and recite Hallelukah. Eventually, everyone became expert in the recital of Hallel and the custom of hearing Hallel from the Chazan and answering Hallelukah eventually became abolished. [See Sukkah ibid Rashi 38b “Miminhaga Dehaleila”; Mefarshim ibid]
 Mishneh Sukkah 39a; M”A 422/5; Admur 488/4
 Pashut, as any area which he did not hear has the same status as one who skipped that area.
 See Mishneh ibid; M”A ibid in name of Rabbeinu Yerucham “He can fulfill the obligation whether for an individual [Yachid] or whether for a congregation”
 M”A ibid in name of Rabbeinu Yerucham
 Mishneh ibid; M”A ibid in name of Rabbeinu Yerucham
 Peri Chadash brought in Biur Halacha ibid
 M”A ibid in name of Rabbeinu Yerucham; Sukkah 38b “If he listened and did not answer-Yotzei”; Tosafus ibid “Shama” explains this to refer to “If he does not know how to read or how to answer the Hallelukah”; So explains also Biur Halacha 422/6 “Hallel”
 Admur 488/4; Michaber 488/2; Megillah 21b
 The reason: Although when two voices are heard simultaneously one cannot properly decipher even one of the voices, as explained in 141/2, nevertheless, since Hallel is beloved onto the congregation they therefore pay very close attention to hear it and are therefore able to hear it well even when many sounds are coming from many people. [Admur ibid; M”A 488/2; Megillah ibid]
 Mishnah Sukkah 8a; M”A 422/5; Kaf Hachaim 422/28
 The reason: As she is exempt from the Mitzvah.
 The reason: As he should have learned to recite Hallel himself, and if he is knowledgeable and still chooses to repeat after a woman then he will be punished for choosing such a Shliach. [ibid]
 Biur Halacha 422/2 “Hallel”; unlike the simple implication in M”A ibid
 M”B ibid concludes with a Tzaruch Iyun
 The reason: As the Hallel of Rosh Chodesh is a mere custom of which men and some women have accepted upon themselves and hence there is no reason to differentiate between a man and a woman. [ibid]
 Admur 479/6 regarding Hallel of the night of the Seder; Peri Chadash brought in Kesher Guda 23/8; Beis Oved 15; Kaf Hachaim 422/27
Other opinions: Some Poskim rule a child that has reached the age of Chinuch may read Hallel on behalf of another, being it is only a Rabbinical command. [Riaz brought in Kneses Hagedola; Kaf Hachaim 422/27]
 The reason: As a child is exempt from all the Mitzvos of the Torah and is only Rabbinically obligated in them in order to educate him in Mitzvos. [Admur ibid]
 M”B ibid concludes with a Tzaruch Iyun regarding women
 Biur Halacha 422/2 “Hallel” regarding having women read on behalf of men; unlike the simple implication in M”A ibid; The same would seemingly apply to a child
The reason: As the Hallel of Rosh Chodesh is a mere custom in which both men and children who have reached the age of Chinuch equally accepted upon themselves and hence there is no reason to differentiate between a man and a child. [Based on Biur Halacha ibid regarding children]
 The Kaf Hachaim ibid does not record any leniency attributed to Rosh Chodesh in this regard
 Admur 62/2; Tosafus Sotah 32a; Kneses Hagedola 422/7; Peri Chadash; Kaf Hachaim 422/26
 Bach 193
 Michaber 422/3; Mishneh Sukkah 38a
 The reason for repeating verses: Many of the verses of Tehillim that are recited in Hallel from Hodu Lahashem and Min Hameitzar are repeated within the Psalm by David Hamelech. Such as the words “Tov lachasos Bahashem.. Tov Lachasos, and other verses of the like. Therefore some places are accustomed to also repeat the latter verses starting from Odecha. [Rashi 38a]
 Tur 422; M”B 422/19; Shaar Hakavanos p. 103; Kaf Hachaim 422/43
Other customs: In Sefarad the custom is not to repeat the verses of Baruch Haba and Keil Hashem. [Tur ibid; See Kaf Hachaim ibid]
 Michaber 422/3
The recital of verses after the Chazan is recorded in the Gemara Sukkah 39b. The reason behind this repetition is to serve as a reminder of the original Takana of the Sages in the recital of Hallel. Originally the congregation would simply listen to the Hallel of the Chazan and recite the word Hallelukah after every stanza. There were a total of 123 Hallelukas said by the congregation. [Rambam Chanukah 3/12] In addition, they would repeat the first verse of each paragraph after the Chazan [Roshei Perakim]. In remembrance of this custom it is accustomed even today to repeat the verse of Hodu after the Chazan. [See Sukkah 39b; Rashi “Mikan”]
 The custom used to be for only the Chazan to recite the stanzas of Yomar, Yomru Nah Beis and Yomru Nah Yirei. The congregation would listen and hence fulfill their obligation. Nevertheless, since at times the congregation does not listen properly to the Chazan’s recital, as well as that the Chazan at times does not have in mind to fulfill their obligation, therefore, it is better for each person to say the Stanzas to himself. [M”A 422/8; M”B 422/20; See Kaf Hachaim 422/44] Practically, so is the custom today.
 Sefer Haminhagim p. 81 [English]; M”B 422/20
 See Kaf Hachaim 422/45 in name of Tosafus 38b and Kol Bo regarding why it is permitted to stop in middle of the verse
 See Hiskashrus 439; Siddur Rav Raskin p. 478
 Sefer Haminhagim p. 69 [English]; Hayom Yom 30th Tishreiy-1st of Cheshvan
 Rama 422/2; Rama 479/1 regarding the night of the Seder; Admur 479/6 regarding the night of the Seder; See also Sefer Haminhagim p. 41
 Admur ibid; M”B 422/17
Other opinions: The custom is to recite the stanzas of Hodu bit not of Ana. [Rama ibid; Gr”a; M”B 422/18; Kaf Hachaim 422/41
 The reason: On days that one does not recite the complete Hallel this is to be done as there are opinions that say that a Zimun of three is considered a congregation which warrants a blessing to be said, and hence in order to say a blessing according to all one should strive to have at least three people. [Lechem Chamudos brought in M”A 422/7; M”B 422/18; Kaf Hachaim 422/39] Furthermore, it is to be done even on days that we recite the complete Hallel in order so one is able to read the Hodu to another person. [Igur 815; Shivlei Haleket brought in M”A ibid] Alternatively, it is because it is a Mitzvah to answer Roshei Perakim when reciting Hallel. [Mordechai brought in M”A ibid]
 M”A 422/7; Admur ibid regarding the night of the Seder
Other opinions: Some Poskim rule the above law only applies to days when the incomplete Hallel is recited due to the first reason cited above. [Lechem Chamudos ibid]
 Admur ibid; Elya Raba 422/11; Kaf Hachaim 422/39
 Admur ibid; M”A 479/2; Taz 479/3; Igur 815; Rosh 10/32
Does this apply to all Hallel or only to Hallel of the night of the Seder? The M”A ibid implies that only the night of the Seder this applies, being that women are obligated in the Mitzvah of Hallel on the night of the Seder just like men. However from the Iggur ibid it is implied that this law applies by all Hallel and not just the night of the Seder. So is also implied from the Taz ibid who states that only the men are obligated in the Hallel, unlike the M”A ibid. Vetzrauch Iyun!
 Admur ibid; M”A ibid; Taz ibid; Igur 815
 Admur ibid
 Sefer Haminhagim p. 69 [English]; Hayom Yom 1st Teves based on gloss of Tzemech Tzedek; Shaar Hakolel 37/8; Siddur Rav Anram Gaon; Rasag; Rambam Megillah 3/10; Abudarham; Rebbe in Haggada Shel Pesach p. 46; See Igros Kodesh 2/147 that Rav Yaakov Landa claimed the Rebbe Rashab would say the word Al, although the Rebbe Rayatz did not do so.
 Siddur Admur; Siddur Rav Shabsi and Yaakov Kopel [Shaar Hakolel 37/9]; Mishnas Chassidim Rosh Chodesh 2/1; Chemdas Yamim; Machberes Hakodesh [Harav Nassan Shapiro] Shaar Rosh Chodesh; Kaf Hachaim 422/57
 Siddur Rav Shabsi and Yaakov Kopel however it is omitted in Siddur Harizal and in Peir Eitz Chaim [Shaar Hakolel ibid]
 This is the name of an angel. Some have the custom of not reciting the names Zevadya due to the prohibition in reciting the name of angels. Hence they say this word in their mind. Nevertheless, Admur writes specifically to say it, seemingly due to that it is also the name of a person in Tanach. [Shaar Hakolel 37/10; See Nefesh Chaim [Falagi] 32; Kaf Hachaim 5/10; Yehuda Ya’aleh 21]
 The reason: Saying the above statement is a Segula for long life. [Mishnas Chassidim ibid]
 Hayom Yom 1st Cheshvan
 Admur 488/3; Michaber/Rama 422/4
 Admur ibid; Rama ibid
The reason: As the recital of Hallel on these days is a Rabbinical obligation and hence receives a stricter status. [Admur ibid]
 Admur ibid; Peri Chadash 422; Kaf Hachaim 422/47
 Michaber 422/4 regarding Rosh Chodesh “One may ask Shalom even in the middle and for one who he must respect, and he may answer Shalom to any individual.”; Admur ibid that Chol Hamoed Pesach has the same status as Rosh Chodesh.
The reason: As on these days the recital of Hallel is only a Minhag and hence has a lesser stringency of Hefsek. [Admur ibid]
 Hefsek Betefilah 4/10 [p. 80] and p. 196; Dinei Uminhagei Rosh Chodesh Chabad 8/12 based on Admur 66/5 [and Chayeh Adam 20/4] that one may not make an interval of Amen between the paragraphs of Birchas Shema; Hiskashrus 441
 Nitei Gavriel Pesach 7/12 [p. 69]; Yabia Omer 2/32; The Peri Megadim 51 and glosses of Rav Akiva Eiger rule it is permitted to make an interval of Amen between the paragraphs of Birchas Shema. [See M”B 66/23]
 See Admur 66/4-5; Siddur Admur
 Admur 66/4; Kaf Hachaim 422/46
 Ketzos Hashulchan 18/2
 Michaber 422/5; Kaf Hachaim 422/49; Admur 488/3 refers the reader to 422; Regarding interval during Shema see 65/1; Regarding an interval during Shofar see M”A 588/2; Regarding an interval during Megillah see M”B 690/18
It is a dispute amongst Rishonim and Poskim in whether an interval invalidates a Mitzvah other than Shemoneh Esrei. The Rif; Rambam and Michaber 65/1 rule one never has to repeat the Mitzvah even if he made an interval due to Ones. The Tosafos; Rosh rule that if one made an interval due to Ones that equals in time to the amount of the Mitzvah, then he must repeat the Mitzvah in all cases. The Rama rules like this opinion regarding Biblical commands [Rama and Admur 65/1] and rules like the Rif regarding Rabbinical commands. Hence according to the Rama, an interval during the reading of Hallel does not invalidate the reading. [Darkei Moshe 422/5; Shaar Hatziyon ibid that it is for this reason that the Rama here did not argue on the ruling of the Michaber] However the Levush; Olas Shabbos; Elya Raba and Bach rule like the Tosafus and Rosh even by Rabbinical commands. The M”A 422/9 concludes that by Rabbinical commands [such as Hallel] one is to repeat the Mitzvah without a blessing. [Biur Halacha 65 “Karah Seirugin”; Kaf Hachaim 690/35; See Kaf Hachaim 588/14]
 Michaber ibid; Implication of Rama [Shaar Hatziyon 422/22]; Darkei Moshe 422
 Implication of M”A 422/9; M”B 422/24 in name of Beis Yosef; Darkei Moshe 422/5; Levush; Kaf Hachaim 422/49; See Admur 65/1
 Tosafus; Rosh; Levush; Olas Shabbos; Elya Raba and Bach. The M”A 422/9 concludes that by Rabbinical commands [such as Hallel] one is to repeat the Mitzvah without a blessing. [Biur Halacha ibid; Kaf Hachaim 690/35; See Kaf Hachaim 588/14]
 See M”A 422/9; M”B 422/24
Other opinions: Some Poskim rule one is to be stringent even regarding those days that half Hallel is recited. [Bach brought in M”A ibid; Shaar Hatziyon 422/23]
 M”A 422/9; M”B 422/25; Kaf Hachaim ibid
 Admur 65/1 regarding the law by Shema
 Michaber 422/7; Admur 473/48; Shivlei Haleket 174
 The reason: The reason Hallel is recited while standing is because it serves as a testimony of praise to Hashem for all the miracles he has performed for us, and all testimonies must be performed standing. Alternatively, it is due to the verse recited in Hallel which states “Hallelu Es Hashem Omdim”. [Shivlei Haleket; Taz 422/4; M”B 422/28]
The reason that Hallel on the night of Pesach is nevertheless recited sitting: As on the night of Pesach all the actions are done in a way of Cheirus/freedom. [Admur ibid]
 M”A 422/11; Elya Raba 422/17; Chayeh Adam 118/9; See Admur 581/1 regarding Shofar
 Biur Halacha 422 “Meumad”; Regarding Shofar: Admur 581/1; Drashos Maharil Shofar; Darkei Moshe 585; M”A 585/1; Peri Chadash 585; Elya Raba 585/1; Birkeiy Yosef 585/4; Shaareiy Teshuvah 585/1; Chayeh Adam 141/6; M”E 585/5; M”B 585/2; Kaf Hachaim 585/4
The reason: As in such a case this leaning is not defined as standing but as leaning. [Admur ibid; See also 607/7]
 The reason: As anytime that standing is required it is forbidden to lean. This is opposed to the law by the Azara in which leaning is permitted, as standing is not required and rather it is only forbidden to sit due to disrespect. [M”A ibid] See Biur Halacha 422 “Meumad” for a discussion on this matter and why leaning by Hallel should be permitted based on the Shivlei Haleket which basis his ruling on the fact that they would stand in the Azara. Nevertheless, he concludes that based on the reason of the verse of Hallelu Es Hashem Omdim one should not lean.
 P”M 422 M”Z 4; M”B 422/28; Kaf Hachaim 422/58; Regarding Shofar: Admur ibid; M”A 585/1; Peri Chadash 585; Elya Raba 585/3; Birkeiy Yosef 585/2; Shaareiy Teshuvah 585/1; Chayeh Adam 141/6; M”E 585/5; M”B 585/2; Kaf Hachaim 585/5
 The reason: As the above obligation to stand is a merely Rabbinical enactment. [Admur ibid regarding Shofar]
 422/6; Megillah 17b
 Michaber ibid; Megillah ibid
The reason: This is learned from the verse “Memizrach Shemesh Ad Mevoa Mehulal Sheim Hashem” that just like the sun travels from east to west, so too the praising of Hashem must follow an exact order and cannot be said retroactively. [M”B 422/26; Megillah ibid]
 M”A 422/10
 M”B ibid based on Michaber 64/1 regarding reading the paragraphs of Shema in the wrong order
 Peri Chadash 422; P”M 422 A”A 9; implication of Olas Tamid 690/6; M”B 422/26 in name of Poskim ibid; Kaf Hachaim 422/50; Implication of Admur 64/1 rules that the reason why by Shema it is valid if the paragraphs are said in the wrong order is because in the Torah itself the paragraphs are not in proximity to each other. This would imply that by Hallel, in which the paragraphs are proximate to each other, it would be invalid.
 The reason: As the order in which we read the Hallel follows the order that they are written in the Torah, and hence it is not similar to Shema. [M”B ibid]
 M”B 422/26; Kaf Hachaim 422/51
 Days in which Hallel is obligatory: Seemingly this applies even during days that Hallel is an obligation. However see M”B ibid which implies that if one read the verses in the wrong order by those days in which Hallel is obligatory, the blessing is to be repeated. However from Kaf Hachaim ibid it implies one never repeats the blessing even in such a case. See also Kaf Hachaim 690/40 and the next footnote in the second reason
 M”B 422/26
The reason: As one who read the paragraphs in the wrong order, some Poskim rule it is valid, and Safek Brachos Lihakel. [M”B ibid] Furthermore, even regarding one who read the verses in the wrong order, seemingly on Rosh Chodesh, being that the entire reading of Hallel is only a custom, and therefore we specifically skip two paragraphs, then Bedieved one should fulfill his obligation, as why should reading in the wrong order be more severe than skipping a verse. Thus, although certainly one should repeat the Hallel in all cases, nonetheless one should not repeat the blessing. [M”B ibid and Biur Halacha 422/6 “Lemafreia”] Another reason not to require the repetition of a blessing is because in any event the invalidation traces back only until the area of disorder, however, all the verses recited until that point are valid. It is thus considered like one who read part of Hallel and then made an interval, in which case we rule that he is simply to continue from where he left off, as an interval does not invalidate the original blessing. [See Halacha H regarding making an interval in Hallel]
 Rama ibid; Rabbeinu Yerucham
 M”A 422/10
 M”B 422/27; Beis Yosef based on Rabbeinu Yerucham; See Biur Halacha 422/6 “Lemakom Shetah” which questions this ruling
 Biur Halacha 422/6 “Lemafreia”
 The reason: As in any event one is initially to skip verses in this Hallel which is due to custom, and there is no set law regarding which areas to skip, even though the custom has become accepted in this matter to only skip two paragraphs. [ibid]
 Admur 131/5
 Admur ibid; M”A 131/10; Taz 422/2 and in Y.D. 376/2; Rokeiach 316; Tanya 68; Kneses Hagedola 422/5; Peri Chadash 422/2; Elya Raba 131/9; Kaf Hachaim 131/61
The reason: The reason for this is because the rectal of the verse “Lo Hameisim YeHalleluka-The dead do not praise G-d” within the house of the mourner is making a mock of the deceased. [Admur ibid; Taz 422 ibid in name of Rokeiach]
Other opinions: Some are accustomed to recite Hallel on Rosh Chodesh in the Beis Havel. [Minhag Sefarad brought in Kneses Hagedola and Peri Chadash ibid; Kaf Hachaim ibid]
 Admur 131/5 in parentheses; Kaf Hachaim 131/61 “So seems to be the main ruling”; See Chikrei Halachos 7/28 that Admur placed this ruling in parentheses due to the dissenting opinions brought next
The reason: (As the obligation to recite Hallel applies throughout the day and is not obligated to be said immediately after Shemoneh Esrei. This can be seen from the fact that at times the Sages instituted for it to be said even before the prayer, as explained in 422. It goes without saying that it may be said after the prayer, anytime throughout the day. This applies even for one praying in private on Rosh Chodesh. It was only instituted to be said immediately after the prayers due to “Zerizim Makdimim Lemitzvos”. [It is thus not similar to the saying of Tachanun which is not repeated after leaving the house of the Avel, as Tachanun was instituted to be specifically said after Shemoneh Esrei and hence once it was differed it is no longer said even upon the individuals return home.] Furthermore, [it is not similar to Tachanun as] Tachanun was exempt from being said during its obligatory time due to the mourning of the Avel to which the day is like his holiday. However Hallel was never exempted from being said and it is simply that it cannot be said in the house of the mourner due to “Loeg Larash”. Therefore, they are required to leave the house and read Hallel just like one who is praying on the road and met a cemetery immediately after Shemoneh Esrei in which case he must move away from the cemetery in order to say Hallel.) [Admur ibid parentheses in original]
Other opinions: Some Poskim rule one is not required to recite Hallel after leaving the Beis Havel. [M”B 131/20; implication of M”A 131/10; Poskim brought in Kaf Hachaim ibid]
 The reason: The above law of skipping Hallel in the house of an Avel only applies by Hallel said on Rosh Chodesh being that its obligation is merely due to custom. However on Chanukah in which Hallel is said as an obligation due to Rabbinical decree, it is recited even in the mourners home, as even the mourner himself is obligated to recite it. [Admur ibid]
 Admur ibid; Sefer Haminhagim p. 161
 The reason: The congregation is found in a state of joy during this time similar to the custom on Shabbos and Yom Tov [and it is hence improper for the Avel to lead the prayers].
 Likkutei Torah Tzav page 28
If one is in doubt as to whether he said Hallel on Rosh Chodesh, or whether he said it correctly, what should he do?
Seemingly, he should repeat it without a blessing, as it is not a big deal to do this in order to be certain that he has complied with the mitzvah.