Leviticus 9:8-9, 18

So Aaron drew near to the altar and killed the calf of the sin offering, which was for himself. And the sons of Aaron presented the blood to him, and he dipped his finger in the blood and put it on the horns of the altar and poured out the blood at the base of the altar.

Then he killed the ox and the ram, the sacrifice of peace offerings for the people. And Aaron’s sons handed him the blood, and he threw it against the sides of the altar.