“…And you will return to Hashem your G-d, and you will listen to His voice…” – Devarim 30:2

וְשַׁבְתָּ עַד ה’ אֱלֹקֶיךָ וְשָׁמַעְתָּ בְקֹלוֹ – דברים ל, ב

The Sefer Mitzvos Katan (#53) interprets this verse as a command to do teshuvah; meaning, one has a positive obligation to repent, and has neglected a mitzvah if he does not. Others, however, interpret this verse as foretelling that the Jewish people will ultimately repent, (see, for example, Rambam, Hilchos Teshuvah 7:5,) but not necessarily as a commandment to do so. In fact, according to some opinions, repentance is truly not a mitzvah of its own (see Minchas Chinuch, #364).

This debate reflects two aspects of teshuvah as explained in the teachings of Chassidus. According to Chassidus, the soul is comprised of 613 spiritual “limbs” or faculties, each corresponding to another mitzvah (Tanya, Chapter 4). A deficiency in the fulfillment of a mitzvah causes a deficiency in the corresponding limb in one’s soul (Likutei Torah, Nitzavim 45c).

Teshuvah, however, has the ability to repair the limbs of the soul that have been damaged through sin. This is because the profound desire and drive to reconnect with G-d expressed in teshuvah draws from the very essence of the soul, the source from which the individual limbs of the soul extend. Teshuvah thus draws new life into all the limbs of the soul, restoring them to their proper “health”.

This explains the opinion that teshuvah is not one of the commandments. Feelings that stem from the depths of your heart, expressing the essence of your soul, must come from within; when you act out of duty, you are not expressing your most natural self. Therefore, the Torah does not command us to repent, according to one opinion, since only when teshuvah is motivated by your own free choice is it clear that it stems from the purest essence of your soul.

Nevertheless, the prevalent opinion is that teshuvah is, in fact, a mitzvah (see Tanya, Iggeres Hateshuva, Chapter 1). For the goal of teshuvah is not only (to regret the past and) to have a burning desire to return to G-d, but the practical observance of G-d’s commands that these feelings will bring about in the future. Therefore, though teshuvah must stem from within and not be motivated by duty alone, it is nevertheless a mitzvah like all the others, in order to remind us its objective—to reinvigorate our fulfillment of the mitzvos, our obligations toward G-d.

-Likutei Sichos, vol. 38, pp. 18-25