Leviticus 16:5-8

And he shall take of the congregation of the children of Israel two he-goats for a sin-offering, and one ram for a burnt-offering. And Aaron shall present the bullock of the sin-offering, which is for himself, and make atonement for himself, and for his house. And he shall take the two goats, and set them before Jehovah at the door of the tent of meeting. And Aaron shall cast lots upon the two goats; one lot for Jehovah, and the other lot for Azazel.