G‑d then summoned Moses to Mount Sinai for a third 40-day stay. During this stay, G‑d revealed His thirteen attributes of mercy to Moses. By invoking these attributes, it would always be possible to secure G‑d’s forgiveness.
Elevating the Power within Sin
נֹשֵׂא עָוֹן וָפֶשַׁע וְחַטָּאָה וגו': (שמות לד:ז)
[The 10th, 11th, and 12th attributes of Divine mercy are that G‑d can] forgive premeditated misdeeds, rebellious misdeeds, and unintentional misdeeds. Exodus 34:7

The Hebrew word for “forgive” used in this verse literally means “carry” or “lift.” Based on this, Rabbi Yisrael Ba’al Shem Tov, the founder of Chasidism, taught that G‑d elevates the spark of holiness in the misdeed. Nothing, not even a sin, can exist unless it contains a spark of holiness. When a person repents, G‑d elevates the Divine spark in his misdeed and returns it to its Divine source.

Rabbi Shneur Zalman of Liadi, the founder of the Chabad branch of Chasidism, explained this idea as follows: It is indeed impossible to elevate a sinful act; such an act is evil, and the only proper treatment for it is to renounce it. In contrast, the power of desire vested in the act is not evil, for it is possible to utilize this power to desire good as well as evil. When we repent properly, we divest our power of desire of its veneer of evil and restore it to its holy source.1