Leviticus 23:23-27

23And the Lord spoke to Moses, saying,

24"Speak to the people of Israel, saying, In the seventh month, on the first day of the month, you shall observe a day of solemn rest, a memorial proclaimed with blast of trumpets, a holy convocation.

25You shall not do any ordinary work, and you shall present a food offering to the Lord."

26And the Lord spoke to Moses, saying,

27"Now on 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 and present a food offering to the Lord.