Leviticus 16:29-31

29“This is to be a perpetual statute for you. In the seventh month, on the tenth day of the month, you must humble yourselves and do no work of any kind, both the native citizen and the foreigner who resides in your midst,

30for on this day atonement is to be made for you to cleanse you from all your sins; you must be clean before the Lord.

31It is to be a Sabbath of complete rest for you, and you must humble yourselves. It is a perpetual statute.