Leviticus 9:7-9

New International Version - UK

⁷ 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.’

⁸ So Aaron came to the altar and slaughtered the calf as a sin offering for himself. ⁹ His sons brought the blood to him, and he dipped his finger into the blood and put it on the horns of the altar; the rest of the blood he poured out at the base of the altar.