Leviticus 9:7-9

9:7 Moses then said to Aaron, “Approach the altar and make your sin offering and your burnt offering, and make atonement on behalf of yourself and on behalf of the people; and also make the people’s offering and make atonement on behalf of them just as the Lord has commanded.”

The Sin Offering for the Priests

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