13:20 And if, when the priest seeth it, behold, it [be] in sight lower than the skin, and the hair thereof be turned white; the priest shall pronounce him {g} unclean: it [is] a plague of leprosy broken out of the boil.
(g) No one was exempted, but if the priest pronounced him unclean, he was put out from among the people: as appears by the example of Mary the prophetess, Nu 12:14 and by king Uzziah, 2Ch 26:20.
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, ver. 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.
