Leviticus 14:19; Leviticus 14:31

19 "The priest shall next offer the sin offering and make atonement for the one to be cleansed from his uncleanness. Then afterward, he shall slaughter the burnt offering.

31 "He shall offer what he can afford , the one for a sin offering and the other for a burnt offering, together with the grain offering. So the priest shall make atonement before the LORD on behalf of the one to be cleansed.