Yom Kippurim (literally the Day of Atonement) is commemorated from the ninth day of the seventh month in the evening until the tenth day of the seventh month in the evening (Leviticus 23, 26-32).
Yom Kippurim is described as Shabbat Shabbaton in an emphatic command to rest and refrain from work (Leviticus 23, 28; 23, 32).
On Yom Kippurim, individuals must refrain from work and are to practice “self-denial,” or, literally “self-affliction” (Leviticus 23, 27-32).
Special offerings are mentioned in VaYikra (Leviticus 23, 27) and detailed in Bemidbar (Numbers 29, 1-11). The offerings resemble those which are brought on the first of the seventh month (Rosh HaShana).
Parashat Emor emphasizes the individual's obligation to observe Yom Kippurim, lest he is “cut off” or “lost” from the community and nation (Leviticus 23, 29-30).
Parashat Aharei Mot details the dramatic ritual of atonement carried out by Aharon (the Kohen Gadol, or High Priest). This ritual atones and cleanses the Mikdash and the nation, and is carried out on the tenth of the seventh Month – Yom Kippurim, a day on which no work shall be done by anyone (Leviticus 16, 2-34).
Yom Kippurim is characterized as the annual day of purification and cleansing of sins for the People of Israel (Leviticus 16, 30), enabling a communal fresh start before God, as described on the fiftieth jubilee year called Yovel.
In Parashat Behar the Torah commands the nation to observe to Yovel, the fiftieth year, to be ushered in with the sounding of the shofar on the tenth of the seventh month - on Yom Kippurim (Leviticus 25, 9-11). At the outset of Yovel, sold land reverts to the original ancestral portions, and Israelites who had sold themselves as slaves are to be released, as God has the sole dominion over all individuals and the land (Leviticus 25).