18 And if a bad place has come out on the skin and is well again, 19 And on the same place there is a white growth of a bright mark, red and white, then let the priest see it; 20 And after looking at it, if it seems to go deeper than the skin, and the hair on it is turned white, then the priest will say that the man is unclean: it is the leper's disease, it has come out in the bad place. 21 But if, after looking at it, he sees that there are no white hairs on it, and it is not deeper than the skin, and it is not very bright, then let the priest keep him shut up for seven days: 22 And if it is increasing on the skin, the priest will say that he is unclean: it is a disease. 23 But if the bright mark keeps in the same place and gets no greater, it is the mark of the old wound, and the priest will say that he is clean.
Matthew Henry's Commentary on Leviticus 13:18-23
Commentary on Leviticus 13:18-44
(Read Leviticus 13:18-44)
The priest is told what judgment to make, if there were any appearance of a leprosy in old sores; and such is the danger of those who having escaped the pollutions of the world are again entangled therein. Or, in a burn by accident, verse 24. The burning of strife and contention often occasions the rising and breaking out of that corruption, which proves that men are unclean. Human life lies exposed to many grievances. With what troops of diseases are we beset on every side; and thy all entered by sin! If the constitution be healthy, and the body lively and easy, we are bound to glorify God with our bodies. Particular note was taken of the leprosy, if in the head. If the leprosy of sin has seized the head; if the judgment be corrupted, and wicked principles, which support wicked practices, are embraced, it is utter uncleanness, from which few are cleansed. Soundness in the faith keeps leprosy from the head.