Leviticus 9:7-9

⁷And Moses said to Aaron, Draw nigh to the altar, and offer thy sin-offering, and thy whole-burnt-offering, and make atonement for thyself, and for thy house; and offer the gifts of the people, and make atonement for them, as the Lord commanded Moses.

⁸And Aaron drew nigh to the altar, and slew the calf of his sin-offering.

⁹And the sons of Aaron brought the blood to him, and he dipped his finger into the blood, and put it on the horns of the altar, and he poured out the blood at the bottom of the altar.