Forty days after they received the Torah at Mount Sinai and committed to be G‑d’s chosen people, the Children of Israel worshipped a Golden Calf. Moses pleaded with G‑d not to destroy His errant nation, and on the tenth of Tishrei G‑d said, “I have forgiven.” Ever since, we observe this date as the “Day of Atonement”—a celebration of our indestructible relationship with G‑d. It is the holiest day of the year, when we reconnect with our very essence, which remains faithful to G‑d regardless of our behavior.
Yom Kippur is a fast day: from sundown on the eve of Yom Kippur until the following nightfall, we do not eat or drink. (If you’re ill, consult a rabbi.) We also abstain from certain physical pleasures: wearing leather footwear, bathing or washing, applying lotions or creams, and marital relations. It is also a “day of rest,” on which all work is forbidden (as on Shabbat).
We wear white clothes in emulation of the spiritual angels
We wear white clothes in emulation of the spiritual angels, and spend the greater part of the day in the synagogue engaged in repentance and prayer. There are five prayer services: 1) The evening prayers, which begin with the solemn Kol Nidrei. 2) Morning prayer. 3) Musaf, which includes a description of the Yom Kippur Holy Temple service. 4) Afternoon prayer, during which the Book of Jonah is read. 5) Ne’ilah, recited as the day wanes and the verdict for the new year is sealed. The first four prayers include a (private) confession of sins to G‑d.