Leviticus 9:5-7

5 ¶ And they brought that which Moses commanded before the tabernacle of the congregation: and all the congregation drew near and stood before the Lord. 6 And Moses said, This is the thing which the Lord commanded that ye should do: and the glory of the Lord shall appear unto you. 7 And Moses said unto Aaron, Go unto the altar, and offer thy sin offering, and thy burnt offering, and make an atonement for thyself, and for the people: and offer the offering of the people, and make an atonement for them; as the Lord commanded.