Chasidut על שבת 156:16

Or we can say "if one hasn't repaid it" (Shabbat 78b:7) that behold, a person has inside a piece of Godliness Above, and even when one transgresses, God forbid... were it not for that Godly piece inside, a person would have no strength to move any part of their body to do anything. And [in a transgression] there is forcing of that Godly piece to cover itself with coverings since those coverings make it possible for that piece to suffer through the great pain of the transgression, and this is secret of the exile of the Shechinah. And after, when a person repents (returns/does teshuvah) and cries over their transgressions, they cry over the exile of the Shechinah, and through this they destroy the coverings that the Godly piece was forced to wear, and reveal, through the fixing (tikkun) of the transgression [the Shechinah]. And this is the meaning in "until one has not repaid" - that is, one has not removed and revealed the coverings from the Godly piece, one has not yet done teshuvah as needed, so one is "obligated." "And if one has repaid, one is exempt", as explained above. "Rabbi Yehudah says etc" as explained above.