Leviticus 16:6-11, 21-22, 29-30, 34

Then Aaron shall present the bull as the sin offering for himself, and make atonement for himself and for his house. He shall take the two goats and present them before the LORD at the doorway of the Tent of Meeting. Aaron shall cast lots for the two goats—one lot for the LORD, the other lot for the scapegoat. Then Aaron shall bring the goat on which the LORD’S lot fell and offer it as a sin offering. But the goat on which the lot fell for the scapegoat shall be presented alive before the LORD to make atonement on it; it shall be sent into the wilderness as the scapegoat. “Aaron shall present the bull as the sin offering for himself and make atonement for himself and for his household (the other priests), and he shall kill the bull as the sin offering for himself.

Then Aaron shall lay both of his hands on the head of the live goat, and confess over it all the wickedness of the sons of Israel and all their transgressions in regard to all their sins; and he shall lay them on the head of the goat [the scapegoat, the sin-bearer], and send it away into the wilderness by the hand of a man who is prepared [for the task]. The goat shall carry on itself all their (the Israelites) wickedness, carrying them to a solitary (infertile) land; and he shall release the goat in the wilderness. [Ps 103:12; Is 53:11, 12; John 1:29]

“This shall be a permanent statute for you: in the seventh month (nearly October) on the tenth day of the month you shall humble yourselves [by fasting] and not do any work, whether the native-born or the stranger who lives temporarily among you; for it is on this day that atonement shall be made for you, to cleanse you; you will be clean from all your sins before the LORD. [Heb 10:1, 2; 1 John 1:7, 9]

This shall be a permanent statute for you, so that atonement may be made for the children of Israel for all their sins once a year.” So he did just as the LORD had commanded Moses.