The priest shall examine it, and if it appears to be beneath the skin and the hair in it has turned white, the priest shall pronounce him unclean; it is a diseased infection that has broken out in the boil.
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, when the priest seeth it,.... And has thoroughly viewed it and considered it: behold, it be in sight lower than the skin; having eaten into and taken root in the flesh under the skin: and the hair thereof be turned white; which are the signs of leprosy before given, Lev 13:3, the priest shall pronounce him unclean; not fit for company and conversation...
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 unclean: it [is] a plague of leprosy broken out of the boil.