the priest shall examine the infection, and if it appears to be deeper than the skin and the hair in it is yellow and thin, the priest must pronounce him unclean; it is a scaly outbreak, an infectious disease of the head or chin.
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, Lev 13:18, etc. 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...
Commenting on Leviticus 13:18-37
And if the priest look on the plague of the scall,.... As it may appear in another person, brought to him for inspection and examination: and, behold, it be not in the sight deeper than the skin; it do not seem to be got into the flesh, or lower than the skin: and that there is no black hair in it; or, "but no black...
Then the priest shall see the plague: and, behold, if it [be] in sight deeper than the skin; [and there be] in it a yellow thin hair; then the priest shall pronounce him unclean: it [is] a dry scall, [even] a leprosy upon the head or beard. (i) Which was not wont to be there, or else smaller than in any other part of the body.