Yom Kippur (Hebrew: יוֹם כִּפּוּר, IPA: [ˈjom kiˈpuʁ], or יום הכיפורים), also known as Day of Atonement, is the holiest day of the year for the Jewish people. Its central themes are atonement and repentance. Jewish people traditionally observe this holy day with a 25-hour period of fasting and intensive prayer, often spending most of the day in synagogue services. Yom Kippur completes the annual period known in Judaism as the High Holy Days or Yamim Nora'im ("Days of Awe").
Yom Kippur is the tenth day of the month of Tishrei and also regarded as the “Sabbath of Sabbaths”. According to Jewish tradition, God inscribes each person's fate for the coming year into a book, the Book of Life, on Rosh Hashanah, and waits until Yom Kippur to "seal" the verdict. During the Days of Awe, a Jewish person tries to amend his or her behavior and seek forgiveness for wrongs done against God (bein adam leMakom) and against other human beings (bein adam lechavero). The evening and day of Yom Kippur are set aside for public and private petitions and confessions of guilt (Vidui). At the end of Yom Kippur, one hopes that they have been forgiven by God.
The Yom Kippur prayer service includes several unique aspects. One is the actual number of prayer services. Unlike a regular day, which has three prayer services (Ma'ariv, the evening prayer; Shacharit, the morning prayer; and Mincha, the afternoon prayer), or a Shabbat or Yom Tov, which have four prayer services (Ma'ariv; Shacharit; Mussaf, the additional prayer; and Mincha), Yom Kippur has five prayer services (Ma'ariv; Shacharit; Musaf; Mincha; and Ne'ilah, the closing prayer). The prayer services also include private and public confessions of sins (Vidui) and a unique prayer dedicated to the special Yom Kippur avodah (service) of the Kohen Gadol in the Holy Temple in Jerusalem.