Day of Atonement (Hebrew, Yom Kippur) is the most important day in the Jewish (see Judaism) liturgical year. The importance of this day comes from Leviticus 16:30, “on this day shall atonement be made for you, to cleanse you; from all your sins you shall be clean before the Lord.” In the period of the second Temple, the ritual of Avodah was central feature of the day.
It was commanded that the people “afflict” themselves (Leviticus 23:27) and the sages interpreted that as abstaining from food and drink, from washing, from anointing the body, from wearing leather shoes, and from sexual intercourse (Yoma 8. 1). Following the destruction of the temple, it was believed that the day itself rather than the temple ritual atone for Israel’s sin.
Nevertheless, forgiveness must be sought from those having been wronged, and confession must be made. In many communities, the day before Yom Kippur regarded almost as a feast day, much food is eaten, gifts are given to the poor, and neighbors visit each other to ask forgiveness. (See Kapparot) The Day of Atonement liturgy begins in the evening of 9 Tishri with the Kol Nidrei, all the vows, service in the synagogue. The services continue through the next day until sunset when it is customary to blow the shofar to indicate the end of the fast.
According to the aggadah the Day of Atonement is the day that Moses was given the second tablets of the law, and it was said that even if all other festivals were abolish, the Day of Atonement on which the Israelites resemble the angels would remain (PRE 46). Today, even very assimilated Jews remember and to some extent observe the day. A.G.H.
Bowker, John, The Oxford Dictionary of World Religions, New York, Oxford University Press, 1997, p. 263