Sefer HaChinuch ספר החינוך

To not detach signs of tzaraat (a Biblical skin disease): That we have been prevented from cutting off signs of tzaraat or to burn it to the point that its appearance changes. And about this is it stated (Deuteronomy 24:8), “Be careful with the blemish of tzaraat, etc. And the language of Sifrei is “‘Be careful with the blemish of tzaraat’ is a negative commandment.” And the language of the Mishnah Negaim 7:4 is “One who removes the signs of impurity or burns the healthy patch of skin transgresses a negative commandment.”

I have written about the roots of this commandment in the Order of Eeshah Ki Tazria [regarding] “and do not shave the scab” (Sefer HaChinukh 170).

Among the laws of the commandment is what they, of blessed memory, said (see Mishneh Torah, Defilement by Leprosy 10:1) that one who detaches signs of impurity — whether all of them or part of them; or even if he burns a healthy patch of skin, completely or even partially; whether from [his] flesh or from a garment or from the house; whether before the priest sees the blemish or during the days of tentative quarantine or during the days of definite quarantine or even after he is [deemed] exempt — in all of these, he transgresses a negative commandment and is liable for lashes. About this it states, “Be careful with the blemish of tzaraat to guard exceedingly and to do like all that the priests, the Levites, instruct you to do; as I commanded them, be careful to do” — meaning to say, “as I commanded them, be careful to do” and do not remove or cut off the blemish. And the well-known principle already preceded us (Makkot 13b) that in every place where it states, “be careful,” or “lest” or “do not,” it is nothing but a negative commandment. And they, may their memory be blessed, said (see Mishneh Torah, Defilement by Leprosy 10:1) that a person is only lashed for this when his actions are effective for him — meaning to say that in the removal of that which he removed of the blemish, there remained less than the required amount [for impurity] in the remnant. But if there remained the amount [needed] for impurity in the remnant — for example, if there was a bright spot and there were three white hairs in it and he detached one, or if he burned part of the healthy skin and there remained part of it the size of a lentil — he is not lashed; as behold, he is [still] impure as at first. And so [too], all that is similar to this. But we [rather] strike him with lashes of rebellion. And the matter is not like this with a scab, as he is not lashed for a scab in his shaving part of the scab — until he shaves all of it, as I wrote in its place in the Order of Eeshah Ki Tazria (Sefer HaChinukh 170).

And they, may their memory be blessed, said (Shabbat 132b) about the matter of this prohibition that one who has tzaraat on his foreskin should not have a concern about circumcising, as the positive commandment of circumcision pushes off this negative commandment; [just] like we hold in every place, that a positive commandment comes and pushes off a negative commandment. And that is when it is impossible to fulfill the positive commandment without the negation of the negative commandment — for example, this [case of] circumcision with tzaraat. And the Sages, may their memory be blessed, learned (Yevamot 3b) that this law was not said generally with all negative commandments, but rather only with a light negative commandment, meaning to say one that doesn’t come with excision (karet). [This is] as in the case of the negative commandment of “You shall not wear shaatnez” (Deuteronomy 22:11), which we push off with the positive commandment of “You shall make for yourselves tassels.” And so too, this negative commandment of not cutting off his bright spot, where there is also no excision — with these and with similar to them, behold, the thing is as if the Torah said explicitly, “I have not prevented you in the case of this positive commandment.” But with any negative commandment that comes with excision, we do not push [them] off because of a positive commandment. Since the verse was so stringent about it to obligate him excision, behold it is as if it stated explicitly, “Do thing x, so long as you will not need to transgress negative commandment y in doing it.” And the rest of the details of this commandment are elucidated in Tractate Negaim (Chapter 7).

And this prohibition is practiced in every place and at all times by males and females, such that one who contracts tzaraat and recognizes the signs of his tzaraat is not permitted to cut them off. And one who transgresses this and detaches them in the way that we mentioned is liable for lashes.