Leviticus 16:29-31

“And it shall be a statute to you forever that in the seventh month, on the tenth day of the month, you shall afflict yourselves and shall do no work, either the native or the stranger who sojourns among you. For on this day shall atonement be made for you to cleanse you. You shall be clean before the LORD from all your sins. It is a Sabbath of solemn rest to you, and you shall afflict yourselves; it is a statute forever.