18 'And when flesh hath in it, in its skin, an ulcer, and it hath been healed, 19 and there hath been in the place of the ulcer a white rising, or a bright white spot, very red, then it hath been seen by the priest, 20 and the priest hath seen, and lo, its appearance 'is' lower than the skin, and its hair hath turned white, and the priest hath pronounced him unclean; it 'is' a plague of leprosy—in an ulcer it hath broken out. 21 'And if the priest see it, and lo, there is no white hair in it, and it is not lower than the skin, and is become weak, then hath the priest shut him up seven days; 22 and if it spread greatly in the skin, then hath the priest pronounced him unclean, it 'is' a plague; 23 and if in its place the bright spot stay—it hath not spread—it 'is' an inflammation of the ulcer; and the priest hath pronounced him 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.