Leviticus 14:12 - Ellicott's Commentary On The Whole Bible

And offer him for a trespass offering. — As leprosy was a Divine punishment for sin, the restored leper had to bring expiatory sacrifices. There is, however, a striking difference in the ritual of the leper’s trespass offering and the ordinary trespass offering described in Leviticus 5:6, &c. In the case before us, not-only did oil accompany it, but both the trespass offering and the oil were waved by the priest, which did not take place on any other occasion in connection with the trespass offering and sin offering. Indeed, in no other case was the entire victim waved before the Lord.