The special nature of Yom Kippur is expressed through the mitzvot of the day. Three of its mitzvot are shared by other holy days:
- Making it a sacred occasion, by designating it for holy purposes and honoring it with nice clothes and a clean house. As we read: “The tenth day of this seventh month is the Day of Atonement. It shall be a sacred occasion for you” (Vayikra 23:27). This is explained further in 7:1 below.
- Abstaining from melakha, just as we abstain on Shabbat. As we read: “You shall do no work throughout that day. For it is a Day of Atonement, on which atonement is made on your behalf before the Lord your God…. And whoever does any work throughout that day, I will cause that person to perish from among his people. Do no work whatsoever; it is a law for all time, throughout the ages, in all your settlements” (ibid. 28-31). This is explained further in 7:2 below.
- Offering musaf sacrifices, like other holidays and Rosh Ḥodesh, as we read: “You shall present to the Lord a burnt offering of pleasing odor: one bull of the herd, one ram, seven yearling lambs; see that they are without blemish…. And there shall be one goat for a sin offering, in addition to the sin offering of expiation and the regular burnt offering with its meal offering, each with its libation” (Bamidbar 29:8-11).
Additionally, three mitzvot are unique to Yom Kippur:
- Fasting, as we read: “The Lord spoke to Moshe, saying: The tenth day of this seventh month is the Day of Atonement. It shall be a sacred occasion for you: you shall afflict yourselves, and you shall bring an offering by fire to the Lord…. Indeed, any person who does not afflict himself throughout that day shall be cut off from his kin…. It shall be a Shabbat of complete rest for you, and you shall afflict yourselves; on the ninth day of the month at evening, from evening to evening, you shall observe this your Shabbat” (Vayikra 23:26-32; also see Vayikra 16:29; Bamidbar 29:7).
- Repenting and confessing our sins, as we read: “For on this day, atonement shall be made for you to purify you of all your sins; you shall purify yourselves before the Lord” (Vayikra 16:30). The meaning of “You shall purify yourselves” is “You shall repent” (MT, Laws of Repentance 2:7; Sha’arei Teshuva 4:17).
- Offering a special set of sacrifices to atone for the sins of Israel, climaxing with the Kohen Gadol entering the Kodesh Ha-kodashim, where he offered incense and sprinkled blood from the sin offerings. The special offerings of Yom Kippur included: a bull as a sin offering, atoning for the Kohen Gadol and the other kohanim; a ram as a burnt offering; and two goats as sin offerings, one for God and one for Azazel. The Kohen Gadol sprinkled blood from the bull and from the goat designated for God, first inside the Kodesh Ha-kodashim, and then on the parokhet and the golden altar. The goat of Azazel carried the sins of Israel to an appropriate place in the desert. (See chapter 10 below.)
Nowadays, with the Temple laid waste, Yom Kippur itself atones for Israel, together with fasting and repentance. To a certain extent, the prayers of the day, especially the Musaf prayers, take the place of the sacrifices (MT, Laws of Repentance 1:3; below 10:18).