Leviticus 9:8-9, 18

Aaron therefore went to the altar and killed the calf of the sin offering, which was for himself. Then the sons of Aaron brought the blood to him. And he dipped his finger in the blood, put it on the horns of the altar, and poured the blood at the base of the altar.

He also killed the bull and the ram as sacrifices of peace offerings, which were for the people. And Aaron’s sons presented to him the blood, which he sprinkled all around on the altar