Then the priest shall see the plague
The person on whom it is shall come or be brought unto him; and he shall look upon it and examine it: and, behold, if it [be] in sight deeper than the skin;
which is always one sign of leprosy; [and there be] in it a yellow thin hair;
like the appearance of thin gold, as the Targum of Jonathan; for, as Ben Gersom says, its colour is the colour of gold; and it is called thin in this place, because short and soft, and not when it is long and small; and so it is said, scabs make unclean in two weeks, and by two signs, by thin yellow hair, and by spreading, by yellow hair, small, soft, and short F20: now this is to be understood, not of hair that is naturally of a yellow or gold colour, as is the hair of the head and beard of some persons, but of hair changed into this colour through the force of the disease; and so Jarchi interprets it, black hair turned yellow; in other parts of the body, hair turned white was a sign of leprosy, but here that which was turned yellow or golden coloured: Aben Ezra observes, that the colour expressed by this word is, in the Ishmaelitish or Arabic language, the next to the white colour: then the priest shall pronounce him unclean;
declare him a leper, and unfit for company, and order him to do and have done for him the things after expressed, as required in such a case: it [is] a dry scall;
or "wound", as the Septuagint version; "nethek", which is the word here used, Jarchi says, is the name of a plague that is in the place of hair, or where that grows; it has its name from plucking up; for there the hair is plucked away, as Aben Ezra and Ben Gersom note: [even] a leprosy upon the head or beard;
as the head is the seat of knowledge, and the beard a sign of manhood, and of a man's being arrived to years of discretion; when wisdom and prudence are expected in him; this sort of leprosy may be an emblem of errors in judgment, of false doctrines and heresies imbibed by persons, which eat as doth a canker, and are in themselves damnable, and bring ruin and destruction on teachers and hearers, unless recovered from them by the grace of God.
F20 Negaim, c. 10. sect. 1.