Lack of action versus lack of intent in Halacha:
The Talmud and Poskim rule that thought is unlike speech, and one who thinks the words of Shema without verbalizing them does not fulfill the Mitzvah. This applies even if he concentrates on the words in his mind and heart with all his might and strength, nonetheless, he does not fulfill his obligation, and is required to repeat the reading. The same applies to Birchas Hamazon which is Biblical, as well as all other Rabbinical Mitzvos, and prayer. On the other hand, if one verbalized the words, but did not have intent of the heart, he nevertheless fulfills his obligation, Bedieved, and is not required to repeat the prayer with exception to the first verse of Shema and the first blessing of Shemoneh Esrei [and Birchas Hamazon]. The reason for this is as follows:
The G-dly soul requires no fixing-its purpose is to fix the animal soul:
The [G-dly] soul [i.e. Neshama] does not require any refinement or elevation in it of itself with the fulfillment of Mitzvos, and it is rather performed solely for the sake of refining the animal soul and body. Through speaking with the five parts one’s mouth and performing the Mitzvos with the other limbs of the body, one draws G-dliness to his body and animal soul. [Accordingly, one does not fulfill his obligation with thinking and concentration if it does not involve an action, as it does nothing to fulfill its purpose of refining the animal soul and body. Nonetheless, thought and concentration also play a vital role in the performance of a Mitzvah, as will now be explained.]
Action without intent is like a body without a soul:
The Sages state that prayer or other blessings without intent is like a body without a soul. To understand this we must first give the following introduction in explaining the difference between the soul and body, as found amongst all creations of the world.
Everything, even a rock, has a soul:
Every creation contains a revelation of G-dliness which recreates its body every moment and prevents its return to nothingness. This applies even to the inanimate, such as rock and earth. In addition, every living creature contains a soul which is responsible for giving life to its body, each to their own level, and make the body feel alive. Now, there is no comparison at all between the revelation of G-dly light that shines in the body, and that which shines in the soul of all living creatures.
The concealment of the two forms of G-dliness is equal:
In both the body and soul of a creature, the G-dly light which enlivens it, is concealed and invested in various garments. Being that both the body and soul exist in this world, their G-dly source both go through a descent through the chain of worlds. It goes through tremendously powerful contractions until it is invested in Kelipas Noga and able to enliven this physical and corporal world, which include all the permitted and pure matters of his world. Once it reaches this state of concealment, it can then serve as the medium to draw G-dly energy to the Kleipos and impure matters. Nonetheless, this only refers to the contraction and investment in garments and Kelipas Nogah, however, the intensity of the Divine light allocated to the creations are not equal to all. Some go through a stronger and longer process of contraction, while others are more revealed and expanded.
The difference between the contractions of the G-dly light in the soul versus the body:
In the physical body, and all inanimate creations such as stone and earth, the G-dly ray is found in an incomparable form of contraction. The Divine vitality given to it is so minute that it does not even have the power of growth. In the vegetative kingdom, the Divine revelation is not as contracted as in the inanimate [and thus it has ability to grow]. In general, the level of revealtion is split into four levels, Domeim, Tzomeiach, Chaiy and Midaber which correspond to the four letters of the Divine name of the Tetragrammaton, from where they receive their Divine energy. There is no comparison between the ray of G-dliness that shines within the inanimate and vegetative kingdoms versus the ray that shines within the animal and human kingdom. This is despite the fact that all the levels contain the same concealment of Divine light, and that the Divine light is invested in the same garment of Nogah.
The difference between the physical Mitzvah and its Kavana:
Just as there is no comparison between the ray of G-dliness that shines within the inanimate and vegetative kingdoms versus the ray that shines within the animal and human kingdom, so too there is no comparison between the infinite Divine light of Or Ein Sof which shines and is invested in the physical Mitzvos without intent and the Divine light which shines and is invested in the intents of the Mitzvos. The physical Mitzvos, which include all speech dependent commands, draws down the internal will of Hashem without any concealment or garment at all. Nonetheless, This Divine revelation is incomparable in quality to the Divine revelation of the Or Ein Sof drawn to the Kavana of the physical Mitzvah.
What is Kavana of a Mitzvah?
The Kavana of a Mitzvah is the intent to attach to Hashem [i.e. Dveikus] through fulfilling his will in the performance of the physical Mitzvos, as G-d and His will are one. The same applies for the intent of Tefila and the reading of the Shema and its blessings, and any other blessing, that one’s intent is to attach one’s mind and intellect to Hashem.
The reason Kavana draws a much stronger revelation:
The Kavana of a Mitzvah, which is the Dveikus of the mind and intellect to Hashem, is not in it of itself greater than the Dveikus achieved through the actual physical fulfillment of the Mitzvah. Rather, it is due to the fact that also the Kavana of the Mitzvah is the will of Hashem that its Dveikus is greater, as Hashem desires that one attach one’s mind and intellect to him through the intent of the physical Mitzvos, and the intent of Kerias Shema, Tefila and the other blessings. Now, the ray of Divine will which shines and is invested in the intent is infinitely greater than the ray of the Divine will that shines and is invested in the physical Mitzvos of action and speech themselves, when done without intent.
Like a soul versus a body:
The advantage of the Divine revelation in the Kavana of the Mitzvah is like the advantage of the soul over the body. The body is simply a vessel and garment for the soul, and so too the body of the Mitzvah itself is a vessel and garment for the intent.
The Divine will is the same-The revelation is different:
In both the physical action of the Mitzvah and the intent of the mind, is invested the same will of Hashem which is undefined, and has no change or plurality Heaven Forbid. This Divine will is united with the essence of Hashem in the most absolute unity. Nonetheless, the Divine ray is not equal in them both, in terms of their contraction and dissipation. (As it states in Eitz Chaim that the Kavana’s of the Mitzvos, and the learning of Torah is the aspect of Divine light, while the actual Mitzvos are the level of vessels which are contracted, as through the contraction of the light comes the vessels.)
The four levels in Mitzvos:
The Mitzvos and its Kavana is split to four levels [just as the creations of the world]. The actual physical Mitzvah themselves contain two levels which are the Mitzvos that contain action and the Mitzvos that are fulfilled through speech and thought, such as Talmud Torah, Tefila, Birchas Hamazon and other blessings. The Kavanos of the Mitzvos is likewise split to two levels just as there exists two levels of souls in the animal and human body, the soul of animals and the soul of humans.