Leviticus 16:23-25

23And Aaron shall come into the tent of meeting, and shall put off the linen garments, which he put on when he went into the holy place, and shall leave them there: 24and he shall bathe his flesh in water in a holy place, and put on his garments, and come forth, and offer his burnt-offering and the burnt-offering of the people, and make atonement for himself and for the people. 25And the fat of the sin-offering shall he burn upon the altar.