Leviticus 23:27

27Now aon the tenth day of this seventh month is the Day of Atonement. It shall be for you a time of holy convocation, and you shall afflict yourselves
Or  shall fast; also verse 32
and present a food offering to the Lord.

Leviticus 23:29

29For whoever is not afflicted on that very day cshall be cut off from his people.

Leviticus 23:32

32It shall be to you a Sabbath of solemn rest, and you shall afflict yourselves. On the ninth day of the month beginning at evening, from evening to evening shall you keep your Sabbath.”

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