Leviticus 16:1-6

The LORD spoke to Moses after the death of two of Aaron’s sons when they approached the presence of the LORD and died. The LORD said to Moses, “Tell your brother Aaron that he may not come whenever he wants into the holy place behind the curtain in front of the mercy seat on the ark or else he will die, because I appear in the cloud above the mercy seat. “Aaron is to enter the most holy place in this way: with a young bull for a sin offering and a ram for a burnt offering. He is to wear a holy linen tunic, and linen undergarments are to be on his body. He is to tie a linen sash around him and wrap his head with a linen turban. These are holy garments; he must bathe his body with water before he wears them. He is to take from the Israelite community two male goats for a sin offering and one ram for a burnt offering. “Aaron will present the bull for his sin offering and make atonement for himself and his household.