Leviticus 16:29-34

29This is to be a permanent statute for you: On the tenth day of the seventh month, you shall humble yourselves1 and not do any work—whether the native or the foreigner who resides among you— 30because on this day atonement will be made for you to cleanse you, and you will be clean from all your sins before the LORD. 31It is a Sabbath of complete rest for you, that you may humble yourselves; it is a permanent statute.

32The priest who is anointed and ordained to succeed his father as high priest shall make atonement. He will put on the sacred linen garments 33and make atonement for the Most Holy Place,2 the Tent of Meeting, and the altar, and for the priests and all the people of the assembly. 34This is to be a permanent statute for you, to make atonement once a year for the Israelites because of all their sins.”

And all this was done as the LORD had commanded Moses.