Yom Kippur is the most important holiday of the Jewish year. Jews who do not observe any other Jewish custom will not work on this day. They will fast and attend synagogue services. Yom Kippur occurs on the 10th day of Tishri. The holiday is first talked about in the Old Testament at Leviticus 23:26 et seq.
The name "Yom Kippur" means "Day of Atonement," and that explains what the holiday is about. It is a day set aside to "afflict the soul," to atone for the sins of the past year. On Yom Kippur, G-d enters his judgment of you for the previous year in his book, and then the book is sealed. This day is, essentially, your last appeal, your last chance to change the judgment, to demonstrate your repentance and make amends.
“Yom Kippur” atones only for sins between man and G-d, not for sins against another person. To atone for sins against another person, you must first seek reconciliation with that person, righting the wrongs you committed against them if possible. That must all be done before Yom Kippur.
“Yom Kippur” is a complete Sabbath; no work can be performed on that day. It is well-known that you are supposed to refrain from eating and drinking (even water) on “Yom Kippur”. It is a complete, 25-hour fast beginning before sunset on the evening before “Yom Kippur” and ending after nightfall on the day of “Yom Kippur”. The Talmud, a record of rabbinic discussions pertaining to Jewish law, ethics, customs, and history, also specifies additional restrictions that are less well-known: washing and bathing, anointing one's body (with cosmetics, deodorants, etc.), wearing leather shoes (Orthodox Jews routinely wear canvas sneakers under their dress clothes on “Yom Kippur”), and engaging in sexual relations are all prohibited on “Yom Kippur”.
G-d
A way of avoiding writing the name of G-d, to avoid the risk of the sin of erasing or defacing the Name.
