Kommentar zu Wajikra 13:31

ושער שחור אין בו AND THERE IS NO BLACK HAIR IN IT [THE PRIEST SHALL SHUT HIM UP] — Consequently, if there is black hair in it, he is clean, and does not require to be shut up — for black hair is a characteristic of cleanness in cases of נתקים, as it is stated, (v. 37) “if there is black hair grown up in it … [he is clean]” (Sifra, Tazria Parashat Nega'im, Chapter 8 9).

ושער שחור אין בו והסגיר, if there had been black hair the person would be ritually completely pure and does not need to be isolated even for further examination purposes. This is spelled out clearly in verse 37.

If there was a black hair in it, he is [ritually] clean. [Rashi explains this] so that you will not explain: “And behold! it does not appear deeper than the skin,” even if it has a black hair, and I might think that a black hair is a sign of impurity, or if it has no black hair, even if its appearance is deeper than the skin, it requires confinement, and the ו of ושער שחור is like או (or). Therefore, Rashi explains that everything depends on the black hair, as it says: “And a black hair [grew in it, the nesek is healed, he is clean].”

ושער שחור אין בו, “and there is no black hair on that area of the skin;” this is an additional sign of ritual purity. One may well ask what the situation is if only one of these symptoms is present? The author of b’chor shor states that this depends on the disagreement in the Mishnah between Rabbi Yonatan and Rabbi Yoshiah in the Talmud, tractate Sanhedrin, folio 66. According to one opinion the absence of two symptoms is needed in order for the afflicted person to be declared ritually clean; according to the other opinion the absence either of the two symptoms discussed suffices.

וכי יראה, same as אם יראה, “if or when he sees.”