When Yom Kippur falls on a Shabbat, there is a special reading: Chapter 16 of Leviticus.

Aaron is to bathe himself and then dress up in his special clothes. He is to enter the Holy Shrine with a bull and two hairy goats.

Then he is to kill the bull and sprinkle some of its blood in front of the altar. He is also supposed to sacrifice one of the hairy goats and sprinkle some of its blood too.

Then he is to take the second goat, lean his hands on its head and confess over it all the sins of the Children of Israel. After that, he is to set it free into the wilderness.

After completing the sacrifice of the bull and the hairy goat, by burning their skins, their flesh and their dung, he is to wash himself and his clothes

This is to be done every year on the tenth day of the New Moon (Yom Kippur). It’s “a law for the ages.”

Aaron washes all his clothing and himself then makes these sacrifices on behalf of the people.