Two loves: There are two levels of love, one comes on its own and it has no request of passion to attach [as it already feels the attachment]. The other where it desires the attachment. One is to have this passion to attach to Hashem in prayer and then learn torah and do Mitzvos with great Simcha, as when he does so he attaches to Hashem. This is meaning of serving Hashem with Simcha, to perform the Mitzvos with passion to attach to Him, and rejoice over the attachment. 
Natural love is higher than new love: The hidden love found in a Jew is greater than the independent love that a Jew creates through contemplation.
Intellectual love: At times, as well as in certain souls, it is not possible to arouse a palpable love of G-d in one’s heart. Rather one arouses an intellectual pull towards attaching to G-d, with his heart remaining a distance from this desire. Although this love is not true love of Hashem, nevertheless, since it is a viable motivation and cause for one to perform Torah and Mitzvos and overcome the evil inclination, therefore Hashem considers it as a true love of Him, and attaches it to the actions done. This intellectual desire to cleave to G-d becomes similar to palpable love felt in the heart and acts as the wings to elevate one’s Torah and Mitzvos above to Heaven. These wings help elevate the Mitzvos to the world of Beiryah, just as would occur if there was actual love created in the heart. However to be elevated to Yetzira it anyways suffices to have the natural born love contained hidden in the heart, and one does not need intellectual love to bring it there. On this Chazal state “A good thought Hashem attaches to the action.” On this the verse states “Ki Karov Eilecha Hadavar Meod” as although it is difficult to arouse a palpable love within the heart, it is nevertheless very much within one’s capability to arouse this love in the mind, as every person has control of his thoughts. Through contemplation one can arouse an intellectual desire to cleave to Hashem through his Torah and Mitzvos. A true Rasha however does not have control of his thoughts, as their hearts are in control of their minds and not the opposite. This is a result of their great sin. In order to regain control of the mind over the heart, the Rasha must first do Teshuvah.
The loves of Bechal Levavcha, Nafshecha, Meodecha: The love of Bechol Levavcha is a passion to attach to Hashem that comes from both his animal and G-dly soul. It is triggered by contemplation in Mimalei Kol Almin and how the true life of everything is Elokus. The love of Bechol Nafshecha is a passion to attach to Hashem that comes from the Chaya of the G-dly soul, to the point of Mesirus Nefesh. Meaning, that one desires to expire. It is triggered by contemplation in how everything in creation is a mere ray of G-dliness. The love of Bechol Meodecha is an attachment to Hashem from the Yechida of the soul to the point of absolute nullification where he does Mesirus Nefesh not because he wants to, but because there is no other option as its impossible to separate from G-d. It is triggered by a revelation of Atzmus Or Ein Sof.
 Likkutei Torah Savo 43a
 Torah Or Vayigash 44c
 Tanya chapter 16-17
 Tanya chapter 16
 Tanya chapter 17
 Tanya chapter 17
 Mamar Shuva Yisrael 1977, printed in Melukat 4/6