The priest is here instructed what judgment to make if there was any
appearance of a leprosy, either, 1. In an old ulcer, or bile, that has
been healed, v. 18, &c. When old sores, that seemed to be cured, break
out again, it is to be feared there is a leprosy in them; such is the
danger of those who, having escaped the pollutions of the world, are
again entangled therein and overcome. Or, 2. In a burn by accident, for
this seems to be meant, v. 24, &c. The burning of strife and contention
often proves the occasion of the rising up and breaking out of that
corruption which witnesses to men's faces that they are unclean. 3. In
a scall-head. And in this commonly the judgment turned upon a very
small matter. If the hair in the scall was black, it was a sign of
soundness; if yellow, it was an indication of a leprosy, v. 30-37. The
other rules in these cases are the same with those mentioned before. In
reading of these several sorts of ailments, it will be good for us, 1.
To lament the calamitous state of human life, which lies exposed to so
many grievances. What troops of diseases are we beset with on every
side! and they all entered by sin. 2. To give thanks to God if he has
never afflicted us with any of these sores: if the constitution is
healthful, and the body lively and easy, we are bound to glorify God
with our bodies.