Our Gemara on Amud Aleph (see Rashi, “aderaba”) discusses the idea that the wine libation, after the blood is sprinkled, represents the joy and relief of obtaining atonement.

The Yalkut Divrei Yosef (Succos) remarks that this is why Succos, in particular, is a time of great rejoicing—more so than the other festivals—since it comes on the heels of having received atonement on Yom Kippur.

Shem MiShmuel (Yom Kippur, chapter 15) elaborates on this theme. The joy of receiving atonement is not merely an aftereffect, but rather an obligation and part of the atonement process. He remarks that somebody who does not thoroughly accept in his heart that he receives forgiveness on Yom Kippur, in fact, suffers a self-fulfilling prophecy. The efficacy of Yom Kippur will be diluted without the internal sense and belief in one’s heart in the forgiveness process. The joy that one experiences after forgiveness is a litmus test for how deeply one believes and internalizes the process.

Psychologically, this resonates as well. Much of our reality is constructed by our personal beliefs. If we live in a world in which we believe in forgiveness, we can be forgiving of others as well as ourselves. Forgiveness of others, middah k’negged middah, inspires forgiveness from God. As the Gemara (Rosh Hashanah 17a) states: “One who overcomes his natural inclination toward judgment and resentment receives similar forgiveness and acceptance from God.”