Sefer HaChinuch ספר החינוך

To not shave the hair of the scab: To not shave the hair of the scab (netek), as it is stated (Leviticus 13:33), “but the scab, he shall not shave” — meaning to say that hair that is on the place of the scab, he shall not shave. And the language of Sifra, Tazria, Parashat Nega’im, Chapter 9:7 is “From where [do I know] that one who detaches the signs of impurity from within his scab, that he violates a negative commandment? As it is stated, ‘but the scab, he shall not shave.’” And the matter is that the priest recognize the signs of impurity in the hairs.

It is from the roots of the commandment to hint that every person should tolerate whatever pain and whatever punishment God, blessed be He, punishes him and not rebel against them. And he should not think that there will be ability in his hand to negate them and to hide them from the creatures. Rather, he should request grace from God, blessed be He — that He should heal the crushing of his afflictions. And this root will also suffice for the negative commandment that he should not cut off his baheret that is in the Order of Ki Tetseh (Sefer HaChinukh 584).

From the laws of the commandment is that which they, may their memory be blessed, said (Mishnah Negaim 10:5), “How does one shave the scab? He shaves outside of it and leaves two hairs adjacent to it, so that he will recognize the expansion. And that which they also said (Sifra, Tazria, Parashat Nega’im, Chapter 9:4) that the shaving is proper by any man, as it is stated, “and he shall be shaved” — and undifferentiated [as it is], it implies by any man. And that which they said that one is not liable until he shaves the entire scab with a razor. And the rest of its details are elucidated in Tractate Negaim. (See Mishneh Torah, Laws of Defilement by Leprosy 10.)

And it is practiced by males and females in every place and at all times that there is a priest that has the wisdom to [recognize these] ailments. And one who transgresses it and shaves the scab is lashed.