Leviticus 16:26-28, 29-31

“The man who takes the goat out to Azazel in the wilderness then will wash his clothes and bathe himself with water. After that he will be permitted to come back into the camp. The bull for the Absolution-Offering and the goat for the Absolution-Offering, whose blood has been taken into the Holy of Holies to make atonement, are to be taken outside the camp and burned—their hides, their meat, and their entrails. The man assigned to burn them up will then wash his clothes and bathe himself in water. Then he is free to come back into the camp.

“This is standard practice for you, a perpetual ordinance. On the tenth day of the seventh month, both the citizen and the foreigner living with you are to enter into a solemn fast and refrain from all work, because on this day atonement will be made for you, to cleanse you. In the presence of GOD you will be made clean of all your sins. It is a Sabbath of all Sabbaths. You must fast. It is a perpetual ordinance.