Albert Barnes Commentary Leviticus 14:19-20

"And the priest shall offer the sin-offering, and make atonement for him that is to be cleansed because of his uncleanness: and afterward he shall kill the burnt-offering; and the priest shall offer the burnt-offering and the meal-offering upon the altar: and the priest shall make atonement for him, and he shall be clean." — Leviticus 14:19-20 (ASV)

The cleansed leper was now in a position to avail himself of the accustomed law of sacrifice as one completely restored. The ewe lamb was now offered on his behalf as a sin-offering, one of the young rams as a burnt-offering, and the fine flour mingled with oil as a meat-offering.