Leviticus 9:1-8

And it happened on the eighth day that Moses called Aaron and his sons and the elders of Israel; and he said to Aaron, “Take a bull calf as a sin offering and a ram as a burnt offering, [each] without blemish, and offer both before the LORD. [Heb 10:10-12] Then say to the Israelites, ‘Take a male goat as a sin offering, and a calf and a lamb, both one year old, without blemish, as a burnt offering, and a bull and a ram as peace offerings to sacrifice before the LORD, and a grain offering mixed with [olive] oil, for today the LORD will appear to you.’ ” So they took what Moses had commanded to the front of the Tent of Meeting, and all the congregation approached and stood before the LORD. Moses said, “This is the thing which the LORD has commanded you to do, so that the glory of the LORD may appear to you.” Moses said to Aaron, “Approach the altar and present your sin offering and your burnt offering and make atonement for yourself and for the people; and present the offering of the people and make atonement for them, just as the LORD has commanded.” [Heb 5:1-5; 7:27] So Aaron approached the altar and killed the calf as the sin offering, which was designated for himself.