Yom Kippur
Day of Atonement

In the seventh month, on the tenth day of the month, you shall afflict your souls, and you shall not do any work. For on that day he shall provide atonement for you to cleanse you from all your sins before the L-RD.

Leviticus 16:29-30

Yom Kippur takes place on the 10th of Tishri and was decreed by G-d in Leviticus 23:26. Almost all Jews whether religious or not will "observe the Kippur" in some form. Most Jews will fast and not work.  Many will attend synagogue services. There are many restrictions mentioned in the Talmud for this day. Jews are not supposed to wash or bath or wear cosmetics or leather. They are to fast from sunset to sunset or a period of 25 hours. Children under nine years and pregnant woman are not allowed to fast. Older children and women who just gave birth are supposed to fast as long as they can, but if they have to eat they are allowed to do so.

During the Days of Awe between Rosh Hashanah and Yom Kippur Jews seek forgiveness from other people; on Yom Kippur they seek forgiveness from G-d. G-d will not atone their sin if they have not asked for forgiveness from the people they sinned against.

The evening service the first night is known as the Kol Nidre, which is named for the prayer that starts the service. The Kol Nidre is the holiest prayer and is said several times on Yom Kippur. It is sung by a cantor in the synagogue and is accompanied by a violin. It is translated into English as:

All vows, obligations, oaths or anathemas, pledges of all names, which we have vowed, sworn, devoted, or bound ourselves to, from this day of atonement, until the next day of atonement (whose arrival we hope for in happiness) we repent, aforehand, of them all, they shall all be deemed absolved, forgiven, annulled, void and made of no effect; they shall not be binding, nor have any power; the vows shall not be reckoned as vows, the obligations shall not be obligatory, nor the oaths considered as oaths.

Most of the day is spent in the synagogue where they pray together and individually. Forgiveness of sin is a community responsibility and said in the plural rather than the singular. There is a special prayer book for Yom Kippur and Rosh Hashanah called the machzor. Orthodox synagogues start their services early and continue until the afternoon, when they go home for a nap and come back for evening services. The final service of the Yom Kippur is known as the Ne'ilah and lasts for an hour. The ark of the covenant is kept open during the service so everyone must stand. At the end of the services end after sunset, there is a blowing of the tekiah gedolah, a long blast on the shofar.

Observant Jews wear white to symbolize pureness and as a reminder of Isaiah 1:18:

Come now, and let us reason together, saith the L-RD: though your sins be as scarlet, they shall be as white as snow; though they be red like crimson, they shall be as wool.