Leviticus 16:6-10

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. And Aaron shall present the goat upon which the lot fell for Jehovah, and offer him for a sin-offering. But the goat, on which the lot fell for Azazel, shall be set alive before Jehovah, to make atonement for him, to send him away for Azazel into the wilderness.