Leviticus 16:23-25

23“Then Aaron shall come into the tabernacle of meeting, shall take off the linen garments which he put on when he went into the Holy Place, and shall leave them there.

24And he shall wash his body with water in a holy place, put on his garments, come out and offer his burnt offering and the burnt offering of the people, and make atonement for himself and for the people.

25The fat of the sin offering he shall burn on the altar.