Yom Kippur, which is also known as the Day of Atonement in the Jewish religion, falls in the month of Tishrei (September or October in the Gregorian calendar). This year, the festival will begin at sundown on Sept. 15 and end at nightfall on Sept. 16.

The day is the culmination of the Days of Awe, which is the period of repentance that begins with the Jewish New Year, Rosh Hashanah. In 2015, the United Nations recognized Yom Kippur as an official holiday.

“Yom Kippur is the holiest day of the year for the Jewish people, and the U.N. should have recognized this holiday many years ago. Today we finally have an official place for the Jewish religion in the world’s Parliament,” the then Israeli Ambassador to the U.N., Danny Danon, had said at the time.

Jewish adults observing the holiday typically will fast for around 25 hours. The first prayer of the day, known as Kol Nidre, is often thought of as the quintessential prayer. Here is a selection of the most important prayers from the five services.

Kol Nidre

“All vows, prohibitions, and oaths, consecrations, whether called ‘konam,’ ‘konas’ or any synonymous term, which we may vow, or swear, or consecrate, or prohibit upon ourselves, from the previous Day of Atonement until this Day of Atonement and from this Day of Atonement until the next Day of Atonement we do repent. All of them are undone, abandoned, canceled, annulled and void, and not in effect. Our vows are no longer vows, and our prohibitions are no longer prohibitions, and our oaths are no longer oaths.”

Al Chet

"For the sin which we have committed before you under duress or willingly.And for the sin which we have committed before you by hard-heartedness. For the sin which we have committed before you inadvertently. And for the sin which we have committed before you with an utterance of the lips. For the sin which we have committed before you with immorality. And for the sin which we have committed before you openly or secretly. For the sin which we have committed before you with knowledge and with deceit. And for the sin which we have committed before you through speech."

Yizkor

“May God remember the soul of my father/mother, my teacher who has gone to his world, because I will — without obligating myself with a vow — donate charity for his/her sake. In this merit, may his/her soul be bound up in the bond of life with the souls of Abraham, Isaac and Jacob; Sarah, Rebecca, Rachel and Leah; and with the other righteous men and women who are in the Garden of Eden; let us say, Amen.”

Sheema

“Blessed be the name of the glory of His kingdom forever and ever.”

Yom Kippur
In this photo, Religious Jewish women pray at the women's section of the Western Wall in the Old City of Jerusalem on Sep. 28, 2017. Getty Images / Thomas Coex