"Speak unto the children of Israel: When a man or woman shall commit any sin that men commit, to commit a trespass against the L·rd, and that soul is guilty. Then they shall confess their sin which they have done; and he shall make restitution for his guilt in full." (Numbers 5:6)

I heard from my Master [the Baal Shem Tov] that the pleasure of sin derives from the sparks of the Primordial Kings that fell during the Shattering [of the Vessels] into the Bright Shell [Kelipat Noga].

The Zohar and Lurianic writings speak of a cataclysmic event at the early stages of the creation called the "Breaking of the Vessels," or the "Death of the Eight Kings," based upon the verse: "These are the kings that reigned in the land of Edom, before there reigned any king over the children of Israel." (Genesis 36:31) According to this teaching, the light that emanated from the G·d-head to fill the vessels of creation was too strong, and the eight lower Sefirot, from Da'at to Malchut, shattered and fell into the Kelipat Noga, a realm of creation that stands between the pure and the impure. (See the Book of Tanya for a full discussion of this level of creation and our relationship to it.)

It is through this very spark that a person comes to repent.

These are the sparks of holiness that are enclothed in and enliven all elements of creation. They are the spiritual root of all physical pleasure, including the pleasure derived from sin. It is the role of human beings to uplift these sparks to their supernal root. This is done through the path of Torah and mitzvot, and in the case of sin, through the act of repentance, as this teaching of the Baal Shem Tov explains.

It is through this very spark that a person comes to repent. For when a person regrets his sins, he uplifts this spark to the Supernal World…

That is, a person who repents literally bears, or lifts up, the sin that he committed and returns the spark of holiness to its source.

…as it is written: "who bears iniquity..." (Exodus 34:7)

[Translation and commentary from Tzafnah Paneach, Teruma 3, p. 90b by Rabbi Dr. Eliezer Shore.]