Leviticus 16:7-10

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.