Negaim, Chapter 10, Mishnah 6. The topic of this perek is nesek, the tzara'as that shows up in the hair of the scalp or of the beard. Our mishnah handles two matters: the shaving that the Torah requires once a week of hesger has run its course, and then the simanei tumah of nesek, what happens when they vanish and later show up again. Since all of it rests on the psukim, we begin in the Chumash.
Vayikra, Parshas Tazria, Perek Yud Gimmel, opens the subject in posuk Chof Tes: "Ve'ish o ishah ki yiheyeh vo nega", a man or a woman upon whom a nega, a plague of some sort, appears, "berosho o vizkono", on the scalp or in the place where the beard grows. "Vera'ah hakohen es hanega": the kohen examines it and finds its shade to be "amok min ha'or," sunken in comparison with the skin. Rashi explains, and this has been our understanding since the opening of the masechta, that the language of depth here indicates a color lighter than the surrounding skin, one of the white shades we have been dealing with all along. "Uvo se'ar tzahov dak": within the spot is a golden hair characterized as dak, and we recall the machlokes whether that word denotes thin or denotes short; either way the hair is a diminished one. "Vetimei oso hakohen", the kohen rules him tamei, "nesek hu, tzara'as harosh o hazakan hu", for this is a nesek, the tzara'as of scalp or of beard.
Why does the Torah mention "amok min ha'or" by nesek?
A question arises here. All through this masechta, whenever nesek came up, we stressed that nesek has no connection to the four whites catalogued in the first perek; those shades are simply not among its simanim. Nevertheless the Torah describes the nesek with the words marehu amok min ha'or, precisely the terminology used for those pale shades.
The resolution lies in the Sifra, and the Rambam formulates the Sifra's teaching in language that is at once wider and tighter. In Hilchos Tumas Tzara'as, Perek Shemini, Halacha Alef, he writes: "Nig'ei harosh vehazakan hu sheyipol hase'ar shebahen mei'ikaro veyisha'er mekom hase'ar ponui", the negaim of scalp and beard consist of the hair growing there dropping out from its root, leaving the place bald and bare; such a spot bears the name "zehu hanikra nesek." He continues: "Ve'ein nesek pachos mikagris hamruba", no nesek is less than the square gris, the shiur we studied earlier in the masechta, which has to fit inside the nega. And then comes the crucial addition: "bein shehu mareh amok bein shelo haya amok", and this holds equally when the spot carries that deep white look and when it does not.
Why, then, did the Torah bother to write umarehu amok min ha'or at all? Here the Rambam, drawing on the Sifra, supplies the reason: "lo ne'emar amok binsakim ela lomar lecha", the term amok was placed by nisokim purely in order to draw an analogy. "Mah mareh amok bidei Shamayim", just as the sunken white of a baheres comes about through Heaven, so the factor that renders a nesek tamei, "af nesek hamitamei," must come about bidei Shamayim. And what is that factor? The bareness, the fact that the hair fell away. That falling has to occur on its own, excluding a case in which a man plucked the hair out over a gris-sized area, where he stays tahor: "lehotzi shenitko adam shehu tahor."
Without the Sifra, the posuk would have left us with an entirely different impression. The Sifra teaches that the whole purpose of the phrase is this comparison: the loss of hair must come about from Heaven and not by human hands.
The psukim leading to our mishnah
The parsha proceeds: if the kohen's inspection turns up no golden hair and no black hairs either, then "vehiskir hakohen es nega hanesek," the kohen shuts him in for seven days, a single week. Posuk Lamed Beis moves to the seventh day: "Vera'ah hakohen es hanega," the kohen looks once more, "bayom hashvi'i." And what does he find? No pisayon, no se'ar tzahov, and again the words amok min ha'or, to be read as we explained, that the loss of the hair was not brought about by a person. Under those conditions the Torah rules "vehiskalach", a shaving takes place, yet "ve'es hanesek lo yegalei'ach", the nesek itself is left alone, and a fresh hesger of "shivas yamim sheinis" is imposed.
That very posuk, vehiskalach, is where our Tanna plants himself. Were a Gemara to be found here, it would presumably have asked tana heicha ka'ei, from what point is the Tanna speaking? His subject is the shaving commanded by the Torah when a week of hesger has run out with no siman tumah in evidence, just as a further hesger is about to be declared.
Keitzad megalchim es hanesek
"Keitzad megalchim es hanesek?" How is the shaving of a nesek carried out? "Megalei'ach chutzah lo," the shaving is performed outside the spot, "umeini'ach shtei se'aros", two hairs are left in place, "somoch lo", immediately alongside it, "kdei sheyehei nikar", so that it should be evident, "im posah", if the nesek expanded.
How do they shave the nesek? He shaves outside of it and leaves two hairs adjacent to it, so that it will be recognizable if the nesek spread.
The Rav explains the working of the posuk. The Torah writes ve'es hanesek lo yegalei'ach, but what hair is there in a nesek to shave? Ulemah hu yesh bo? After all, the hair there has already been uprooted and has fallen out. Rather, the meaning is: when he shaves in the area surrounding the nesek, he is not to shave everything clean. He must leave behind two hairs on the border of the nesek on every one of the four sides, shemeshayeir saviv lanesek shtei se'aros mikol tzad. Those pairs of hairs serve as the boundary markers of the nesek. When the kohen returns at the end of the second week and finds that some of those hairs are now gone, that is the sign that the nesek has spread, that there is pisayon.
Why is this demanded specifically after the opening week? There is an explanation that with an ordinary nega the kohen takes the measure of the spot and can judge a week later whether it grew. In our case a higher degree of caution is called for, so the Torah supplies an exact marker on each of the four sides, and the disappearance of those hairs itself establishes that pisayon occurred.
When a siman tumah leaves and returns
The mishnah now shifts to a fresh topic. "Hechlito bese'ar tzahov, halach se'ar tzahov vechozar se'ar tzahov": a golden hair is an instant siman tumah in a nesek, so picture one whom the kohen declared muchlat on account of a se'ar tzahov, after which the golden hair disappeared and the kohen pronounced him tahor, and later on a golden hair came back. He returns to the very position he occupied earlier. "Vechein bepisayon": the ruling holds equally if pisayon shows up in place of the golden hair. The mishnah enumerates the occasions on which this can happen: at the outset (bitchilah), when the first shavua concludes (besof shavua rishon), when the second shavua concludes (besof shavua sheini), or even after the ptur (le'achar haptur). Certain texts drop bitchilah from this list, since pisayon cannot exist at the very start; it is only ever established once a week has elapsed.
The mishnah then states the reverse case: "hechlito bepisayon, halach hapisayon vechozar hapisayon, vechein bese'ar tzahov": if the hechlet came through pisayon, and the pisayon left and afterward showed up again, or a se'ar tzahov arrived in place of the pisayon, be it as the first shavua closes, as the second closes, or even once a ptur has already been issued, his former standing is restored: "harei hu kemoshehaya."
The principle of the entire second half of the mishnah is therefore one: in every case where a siman tumah of nesek returns, whether it is the same siman that was there originally or the other one, and no matter at which stage it returns, we do not begin his reckoning anew. He resumes the status he held when the siman first appeared: he is muchlat.