Leviticus 14:31-33

³¹the one for a sin-offering, the other for a whole-burnt-offering with the meat-offering, and the priest shall make an atonement before the Lord for him that is under purification.

³²This is the law for him in whom is the plague of leprosy, and who cannot afford the offerings for his purification.

³³And the Lord spoke to Moses and Aaron, saying,