This information is excerpted from the website About.Com.Judiasm.
Yom Kippur (the Day of Atonement) is one of two Jewish High Holy Days. The first High Holy Day is Rosh Hashanah (the Jewish New Year). Yom Kippur falls ten days after Rosh Hashanah on the 10th of Tishrei, which is a Hebrew month that correlates with September-October on the secular calendar.
The purpose of Yom Kippur is to bring about reconciliation between people and between individuals and God. According to Jewish tradition, it is also the day when God decides the fate of each human being.
Although Yom Kippur is an intense holiday it is nevertheless viewed as a happy day. Why? Because if one has observed the holiday properly by the end of Yom Kippur they will have made peace with others and with God.
There are three essential components of Yom Kippur:
- Teshuvah (Repentance)
Yom Kippur is a day of reconciliation, when Jews strive to make amends with people and to draw closer to God through prayer and fasting. The ten days leading up to Yom Kippur are known as the Ten Days of Repentance. During this period Jews are encouraged to seek out anyone they may have offended and to sincerely request forgiveness so that the New Year can begin with a clean slate.
Yom Kippur is the longest synagogue service in the Jewish year. It begins on the evening before Yom Kippur day with a haunting song called Kol Nidre (All Vows). The words of this melody ask God to forgive any vows people have made to God and not kept.
The service on the day of Yom Kippur lasts from morning until nightfall. Many prayers are said but one is repeated at intervals throughout the service. This prayer is called Al Khet and asks for forgiveness for a variety of sins that may have been committed during the year.
When Al Khet is recited people gently beat their fists against their chests as each sin is mentioned. Sins are mentioned in plural form because even if someone hasn’t committed a particular sin, Jewish tradition teaches that every Jew bears a measure of responsibility for the actions of other Jews.
During the afternoon portion of the Yom Kippur service the Book of Jonah is read to remind people of God’s willingness to forgive those who are sincerely sorry. The last part of the service is called Ne’ilah (Shutting). The name comes from the imagery of Ne’ilah prayers, which talk about gates being shut against us. People pray intensely during this time, hoping to be admitted to God’s presence before the gates have been shut.
Yom Kippur is also marked by 25 hours of fasting. There are other fast days in the Jewish calendar, but this is the only one the Torah specifically commands us to observe. Leviticus 23:27 describes it as "afflicting your souls" and during this time no food or liquid may be consumed.
The fast starts an hour before Yom Kippur begins and ends after nightfall on the day of Yom Kippur. In addition to food, Jews are also forbidden from engaging in sexual relations, bathing or wearing leather shoes. The prohibition against wearing leather comes from a reluctance to wear the skin of a slaughtered animal while asking God for mercy.