29 "If a man or woman develops a sore on the head or chin, 30 the priest will offer a diagnosis. If it looks as if it is under the skin and the hair in it is yellow and thin, he will pronounce the person ritually unclean. It is an itch, an infectious skin disease. 31 But if when he examines the itch, he finds it is only skin deep and there is no black hair in it, he will put the person in quarantine for seven days. 32 On the seventh day he will reexamine the sore; if the itch has not spread, there is no yellow hair in it, and it looks as if the itch is only skin deep, 33 the person must shave, except for the itch; the priest will send him back to quarantine for another seven days. 34 If the itch has not spread, and looks to be only skin deep, the priest will pronounce him clean. The person can go home and wash his clothes; he is clean. 35 But if the itch spreads after being pronounced clean, 36 the priest must reexamine it; if the itch has spread in the skin, he doesn't have to look any farther, for yellow hair, for instance; he is unclean. 37 But if he sees that the itch is unchanged and black hair has begun to grow in it, the itch is healed. The person is clean and the priest will pronounce him clean.
Matthew Henry's Commentary on Leviticus 13:29-37
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.