Leviticus

And he shall make an atonement for the holy place, because of the uncleanness of the children of Israel, and because of their transgressions in all their sins: and so shall he do for the tabernacle of the congregation, that remaineth among them in the midst of their uncleanness.

Thus saith the Lord God; In the first month, in the first day of the month, thou shalt take a young bullock without blemish, and cleanse the sanctuary:

And Aaron shall offer his bullock of the sin offering, which is for himself, and make an atonement for himself, and for his house.

And he shall wash his flesh with water in the holy place, and put on his garments, and come forth, and offer his burnt offering, and the burnt offering of the people, and make an atonement for himself, and for the people.

And he shall go out unto the altar that is before the Lord, and make an atonement for it; and shall take of the blood of the bullock, and of the blood of the goat, and put it upon the horns of the altar round about.