15And he killed it, and Moses took the blood, and with his finger put it on the horns of the altar around it and purified the altar and poured out the blood at the base of the altar and consecrated it to make atonement for it.
The blood of the bull was used to purify the altar, making it ready for the various sacrifices. Only here and on the Day of Atonement (Leviticus 16:18) is it said that blood is applied around each of the horns of the altar.
15 And he killed it, and Moses took the blood, and with his finger put it on the horns of the altar around it and purified the altar and poured out the blood at the base of the altar and consecrated it to make atonement for it.