Leviticus 16:29-34

“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. And the priest who is anointed and consecrated as priest in his father’s place shall make atonement, wearing the holy linen garments. He shall make atonement for the holy sanctuary, and he shall make atonement for the tent of meeting and for the altar, and he shall make atonement for the priests and for all the people of the assembly. And this shall be a statute forever for you, that atonement may be made for the people of Israel once in the year because of all their sins.” And Aaron did as the LORD commanded Moses.