Forty days after receiving the Torah at Mount Sinai and committing to be God's chosen nation, the Children of Israel worshipped a Golden Calf. Moses pleaded with God not to destroy His wayward nation, and on the tenth of Tishrei, God said, "I have forgiven." Since then, we observe this date as the Day of Atonement—a celebration of our unbreakable relationship with God. It is the holiest day of the year, when we reconnect with our own essence, which remains faithful to God regardless of our actions.
Yom Kippur is a day of fasting: from sunset on Yom Kippur Eve until the following nightfall, we neither eat nor drink. (If you are ill, consult a rabbi.) We also abstain from certain physical pleasures: wearing leather shoes, bathing or washing, applying lotions or creams, and having marital relations. It is also a “day of rest” on which we do no work (as on Shabbat).
We wear white robes, emulating spiritual angels, and spend most of the day in the synagogue praying and repenting for past mistakes. There are five prayers: 1) The night prayer, which begins with the solemn Kol Nidrei, 2) The Morning Prayer (Shacharit), 3) The additional prayer (musaf) which includes a description of the Yom Kippur service in the Temple, 4) The afternoon prayer (mincha), during which the book of Jonah is read and 5) Neilá, recited as the day ends and the verdict for the new year is sealed. The first four prayers include a private confession of sins before God.
Neilá It concludes with the congregation saying the Shema in unison, and a sound of shofar to mark the end of the day. Then a festive, joyful meal is held, trusting in God's forgiveness.