Leviticus 16:1-5

Now the LORD spoke to Moses after the death of the two sons of Aaron, when they had approached the presence of the LORD and died. The LORD said to Moses: “ T ell your brother Aaron that he shall not enter at any time into the holy place inside the veil, before the mercy seat which is on the ark, or he will die; for I will appear in the cloud over the mercy seat. Aaron shall enter the holy place with this: with a bull for a sin offering and a ram for a burnt offering. He shall put on the holy linen tunic, and the linen undergarments shall be next to his body, and he shall be girded with the linen sash and attired with the linen turban (these are holy garments). Then he shall bathe his body in water and put them on. He shall take from the congregation of the sons of Israel two male goats for a sin offering and one ram for a burnt offering.