Leviticus 13:55

הֻכַּבֵּס‎ ‎ ‎‎‎‏ אחרי AFTER IT IS WASHED — The verbal form is an expression of something done (a passive infinitive). לא הפך הנגע את עינו THE PLAGUE HATH NOT CHANGED ITS COLOR — i. e. it has not become paler than its former colour. והנגע לא פשה AND THE PLAGUE HATH NOT SPREAD — We understand from this that if it has not changed its color and has not spread it is unclean, (although the fact that it has not spread might lead us to suppose that it is clean;here, however, the color has not changed, and so it is unclean). It is, of course, not necessary to state that it is unclean if the colour has not changed but the plague has spread (for the spreading is an additional reason for declaring it unclean). If, however, it has changed its colour, but it has not spread, I would not know what one should do with it. Therefore it states, (v. 50) “And he shall shut up the plague” for a period and examine it again — shut it up whatever the circumstances of doubt may be. This is the opinion of Rabbi Jehuda. But other Sages say that in this case it is undoubtedly unclean as is stated in Torath Cohanim (Sifra, Tazria Parashat Nega'im, Chapter 15 7): and I make mention of this here (instead of doing so on v. 50), in order to explain that verse in its connection with this text. פחתת היא — This is an expression denoting a pit (anything cut out) as in, (II Samuel 17:9) “in one of the pits (פחתים)”. It is as much as to say, it is low-lying — a plague the colour of which is sunk deep (Sifra, Tazria Parashat Nega'im, Chapter 15 8). בגבחתו ‎‎‎ או‎ בקרחתו — Understand this as the Targum does: in its old state (lit., rubbed condition) or in its new state. קרחתו is therefore שחקים (clothes rubbed by wear), old (and consequently ,שחיקותיה is a proper contrast to חדתותיה in the Targum). These words, קרחת and גבחת, although not properly applicable to garments are used here to afford an opportunity for an Halachic derivation, for which there is required an argument deduced from the similarity of phrases: Whence do we know in regard to a plague spreading over the entire surface in the case of garments that it is c1ean? Because the, terms קרחת and גבחת are used in the case of a human being and the terms קרחת and גבחת are used in the case of garments. How is it in the former case? If it has spread over all his body, he is clean (v.13)! So here, also, if it has spread over all the garment it is clean (Niddah 19a). For this reason Scripture here purposely avails itself of the expressions קרחת and גבחת, to make the גז"ש possible. And in regard to its interpretation and its translation in the Targum the following is what it implies: קרחת is an expression denoting “old”, and גבחת is an expression denoting “new” (Sifra, Tazria Parashat Nega'im, Chapter 15 9); and the meaning is just the same as though it were written באחריתו או בקדמותו. at its end or at its beginning, — for קרחת has the meaning of the back- parts (i. e. the end), since גבחת has the meaning of face (front-side, i. e. beginning), as it is written, (v. 41) “And if from the corner towards his face [the hair of his head be fallen] … he is a גבח” — so that קרחת must be all that part which slopes downwards on the skull towards the back. Thus is it explained in Torath Cohanim (Sifra, Tazria Parashat Nega'im, Chapter 10 7).

וְרָאָ֨ה הַכֹּהֵ֜ן אַחֲרֵ֣י ׀ הֻכַּבֵּ֣ס אֶת־הַנֶּ֗גַע וְ֠הִנֵּ֠ה לֹֽא־הָפַ֨ךְ הַנֶּ֤גַע אֶת־עֵינוֹ֙ וְהַנֶּ֣גַע לֹֽא־פָשָׂ֔ה טָמֵ֣א ה֔וּא בָּאֵ֖שׁ תִּשְׂרְפֶ֑נּוּ פְּחֶ֣תֶת הִ֔וא בְּקָרַחְתּ֖וֹ א֥וֹ בְגַבַּחְתּֽוֹ׃

And the priest shall look after the plague is washed: and, behold, if the plague have not changed its colour, and the plague be not spread; it is unclean; thou shalt burn it in the fire; it is a decay on the inner or outer surface.