Leviticus 23:23-27

23The Lord spoke to Moses:

24“Tell the Israelites: In the seventh month, on the first day of the month, you are to have a day of complete rest, commemoration, and trumpet blasts  — a sacred assembly.

25You must not do any daily work, but you must present a food offering to the Lord.”

26The Lord again spoke to Moses:

27“The tenth day of this seventh month is the Day of Atonement. You are to hold a sacred assembly and practice self-denial; you are to present a food offering to the Lord.