Leviticus 9:7-9

Amplified Bible

⁷ 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.”^(A)

⁸ So Aaron approached the altar and killed the calf as the sin offering, which was designated for himself. ⁹ The sons of Aaron presented the blood to him; he dipped his finger in the blood and put some of it on the horns of the altar, and poured out the rest of the blood at the altar’s base;