Yom Kippur

History

The day is established in Leviticus 16 and 23:26-32 and in Numbers 29:7-11. The instruction in Leviticus 23:27 is that "the tenth day of this seventh month is the Day of Atonement. It shall be a sacred occasion for you: you shall practice self-denial." The sunset-to-sunset reckoning is in the text too, at 23:32: "on the ninth day of the month at evening, from evening to evening, you shall observe this your sabbath." The Hebrew Bible also calls the day Shabbat Shabbaton, a sabbath of solemn rest. The phrase "practice self-denial" is the Jewish Publication Society's rendering; what self-denial consists of is nowhere specified.

Leviticus 16 describes what the day looked like when there was a Temple. Aaron took two goats and cast lots over them, "one marked for GOD and the other marked for Azazel." The first was offered; the second was "left standing alive" and then, after Aaron laid both hands on its head and confessed over it "all the iniquities and transgressions of the Israelites," sent into the wilderness "through a designated agent" to "carry on it all their iniquities to an inaccessible region." Britannica, which calls that second goat the scapegoat, adds that the high priest was clothed in white linen and entered the Holy of Holies - permitted only on this day - to offer incense and sprinkle sacrificial blood.

After the Temple was destroyed in 70 CE there was no sacrifice to make, and the day was rebuilt around what remained. Britannica records a Midrashic exchange in which Joshua ben Hananiah mourns that atonement has become impossible and his teacher Johanan ben Zakkai answers him from Hosea 6:6: "For I desire steadfast love and not sacrifice." Sacrifice gave way to repentance, judgment and good deeds, and rabbinic literature gave the day a second name, Yom ha-Din, the Day of Judgment.

The prohibitions were set down in the Mishnah, and they arrived with an argument attached. Mishnah Yoma 8:1 forbids "eating and in drinking, and in bathing, and in smearing oil on one's body, and in wearing shoes, and in conjugal relations" - six activities, which the modern count compresses to five by treating food and drink as one. It then records Rabbi Eliezer permitting a king and a bride within thirty days of her marriage to wash their faces, and a woman after childbirth to wear shoes "because going barefoot causes her pain," followed by the flat sentence: "The Rabbis prohibit these activities."

One element of sacrifice survived in practice rather than in law. Britannica describes kaparot, in which a chicken is waved overhead three times and then slaughtered and given to charity, and notes that the ritual "appears neither in the Torah nor the Talmud but has been in practice since at least the 9th century CE," and that it has drawn objections from rabbis and animal rights activists alike.

How to observe

The fast runs from sunset on the ninth of Tishri until the stars come out the next evening. Britannica puts it at 25 hours; Chabad's article says "nearly 26 hours" while Chabad's own summary of the same article says 25, so take the figure as approximate and the sunset-to-nightfall span as the real rule. Britannica notes that children below the age of bar and bat mitzvah - thirteen for boys, twelve for girls - are not required to fast. Chabad directs anyone who must eat to consult both a medical professional and a rabbi.

The day is unusual for holding five prayer services: Maariv on the eve, with Kol Nidrei; Shacharit, with a reading from Leviticus and the Yizkor memorial prayers; Musaf, which recounts the Temple service; Minchah, which includes the Book of Jonah; and Neilah, the closing of the gates, after which a single shofar blast ends the fast.

Two things worth knowing in advance. Kol Nidre annuls vows only "insofar as they concern oneself" - obligations to other people are expressly excluded, which is the opposite of how it is usually assumed to work. And the forgiveness owed to other people is asked for before the day starts, not during it: Britannica's phrasing is that obtaining forgiveness from one's fellows signifies God's forgiveness. White is worn as a symbol of purity, sometimes as a long robe called a kittel, and gold is avoided because it evokes the golden calf.

If you want one short primary text, read Mishnah Yoma 8:1 on Sefaria. It takes a minute, and the dissent it preserves about the king, the bride and the new mother is a better guide to how the day has been argued over than any summary of it.