Leviticus 9:1-8

On the eighth day Moses summoned Aaron and his sons and the elders of Israel. He said to Aaron, “Take a bull calf for your sin offering and a ram for your burnt offering, both without defect, and present them before the LORD. Then say to the Israelites: ‘Take a male goat for a sin offering, a calf and a lamb—both a year old and without defect—for a burnt offering, and an ox and a ram for a fellowship offering to sacrifice before the LORD, together with a grain offering mixed with olive oil. For today the LORD will appear to you.’ ” They took the things Moses commanded to the front of the tent of meeting, and the entire assembly came near and stood before the LORD. Then Moses said, “This is what the LORD has commanded you to do, so that the glory of the LORD may appear to you.” Moses said to Aaron, “Come to the altar and sacrifice your sin offering and your burnt offering and make atonement for yourself and the people; sacrifice the offering that is for the people and make atonement for them, as the LORD has commanded.” So Aaron came to the altar and slaughtered the calf as a sin offering for himself.