Yom Kippur, (”Day of Atonement”) is the most solemn day of the Jewish year. It is the most solemn, and important, of the Jewish holidays. Its central themes are atonement and repentance.

Jews traditionally observe this holy day with a 25-hour period of fasting and intensive prayer, often spending most of the day in synagogue services. It is a day of communal fasting, and praying for forgiveness for one’s sins. Observant Jews spend the entire day in the synagogue, sometimes with a short break in the afternoon, reciting prayers from a special holiday prayer book called a “Mahzor.” Many non-religious Jews make a point of attending synagogue services, and fasting on Yom Kippur.

Yom Kippur is the tenth, and final day, of the Ten Days of Repentance which begin with Rosh Hashanah. According to Jewish tradition, God, or “YHVH” (”The One Who Was, Is and Shall Be”), inscribes each person’s fate for the coming year into a “book” on Rosh Hashanah, and waits until Yom Kippur to “seal” the verdict.

During the Ten Days of Repentance, a Jew tries to amend their behavior, and seek forgiveness for wrongs done against God and against their fellow man. The evening and day of Yom Kippur are set aside for public and private petitions, and confessions of guilt. At the end of Yom Kippur, one considers one’s self absolved by God.

On the eve of Yom Kippur, before candles are lit, a prefast meal, the “seuda mafseket,” is eaten. During Yom Kippur, adults are required to refrain from eating or drinking for a 25-hour period from one-half hour before sundown until nightfall the next day. By properly preparing your body for this “affliction of the soul,” as it is known, you can reduce the pain and discomfort associated with the fast.

Synagogue services on the eve of Yom Kippur begin with the Kol Nidre prayer. Kol Nidre is a declaration recited in the synagogue before the beginning of the evening service. Though not a prayer, this dry legal formula, and its ceremonial accompaniment, have been charged with emotional undertones since the medieval period, creating a dramatic introduction to Yom Kippur on what is often dubbed “Kol Nidrei night”. It is written in Aramaic, not Hebrew. Its name is taken from the opening words, meaning “All vows.”

The Kol Nidre is not a prayer. It is recited three times on the Day of Atonement, the holiest day of the year, in order to be sure that all have heard, and recited it. It is a sort of contract between man, the individual, and God asking God’s forgiveness for obligations made either unknowingly or under coercion during the previous (not forthcoming) year. It only affects promises made to God, and not promises, or obligations, made to other men.

In other words, it is a plea for forgiveness to God for offenses made to him. It does not negate any obligations made to other men, and only asks God’s pardon for unknowingly offending Him, or for having offended Him, because another forced one to do so (such as the Law of Apostasy; meaning, forcing one to forsake their religion for another).

All vows: “Prohibitions, oaths, consecrations, vows that we may vow, swear, consecrate, or prohibit upon ourselves – from this Yom Kippur until the next Yom Kippur, may it come upon us for good – regarding them all, we regret them henceforth. They will all be permitted, abandoned, cancelled, and null and void, without power and without standing. Our vows shall not be valid vows; our prohibitions shall not be valid prohibitions; and our oaths shall not be valid oaths.”

It is customary to wear white on Yom Kippur, especially for Kol Nidre, and leather shoes are not worn. The following day, prayers are held from morning to evening. The final prayer service, called “Ne’ilah,” ends with a long blast from a horn, a trumpet made from a ram’s horn, the shofar.