“Then he is to slaughter the male lamb in the place where they slaughter the sin offering and the burnt offering, in the Sanctuary area. For the sin offering like the trespass offering belongs to the kohen. It is most holy.
He should lay his hand on the head of his offering and slaughter it at the entrance of the Tent of Meeting. Then Aaron’s sons the kohanim are to splash the blood around on the altar.
Moses then slaughtered it, took the blood and dabbed it onto the horns of the altar with his finger, and so purified the altar. Then he poured out the blood at the base of the altar and consecrated it, to make atonement for it.