Negaim 7:1 - 7:2

אלו בהרות טהורות שהיו בו קודם מתן תורה – whomever had on him leprosy prior to the Giving of the Torah, was not impure on account of that plague after the Giving of the Torah, as it is written (Leviticus 13:2): “When a person has on the skin of his body,” excluding what already was. And all these were also considered, from there they are derived, that we require that the plague would come to be at the time that it is appropriate to be defiled by it and not beforehand, like a convert until he had not converted and a minor until he had not been born. And similarly, all of them.

בקמט ונתגלה – that it was from the outset concealed within the wrinkle/fold and he was ritually pure, because it was in a covered part of the body/posterior, but afterwards, it was revealed.

ובמורדים – meaning to say with boils and burns, the scars that did not deal and did not produce a scab like the husk of the garlic.

עד שלא העלו שער – the plague comes, that it is considered like the skin of the flesh, that is the beginning of defilement. But when the hairs arose, it was pure, for its law is like bald or blanched spots on the head or the beard, but when they became bald, that is, their end is defilement. And similarly, boils, and burnt spots on the skin and baldness, that until they did not come, the plague came, that is defilement. But when the boils, burnt spots on the skin and the baldness came, that is purity. For we require that the boils and the burnt spots on the skin come prior to the swelling/sore, as it is written (Leviticus 13:19): “And a white swelling or a white discoloration streaked with red develops where the inflammation was,”/"והיה במקום השחין שאת" , that the boils precede the swelling/sore and not that the swelling/sore precedes the boils. And when they returned and became a scar, that is defilement.

והיו – that they healed properly/nicely.

רבי אליעזר בן יעקב מטמא – since at the outset the plague came in the skin of the flesh, and it returned at its end to its initial status, we are not concerned about the interruption that is between them.

וחכמים מטהרים – since the purity stopped in the meantime. And the Halakha is according to the Sages.

נשתנו מראיהן – it refers to the bright white spots on the skin that are pure, as for example, that it was like snow until he (i.e., a non-Jew) converted, but when he converted [to Judaism] it became like the lime in the Temple.

כצמר לבן וכקרום ביצה – meaning to say, that at first it was like white wool, and now it became like the membrane/skin of an egg.

נעשית מספחת שאת (it became the scurf/second shade of a swelling/sore) – meaning to say that the swelling/sore became scurf, that it returned to become like its derivative/subcategory. Or that the strong/bright [white] became like its scurf. But he is really explaining to the first clause (i.e., presenting a new interpretation of the Mishnah in order to refute an argument based upon that text), as it is taught [in the Mishnah]: "היתה כשלג ונעשית כסיד ההיכל"/it was as white as snow and it became as white as the lime in the Temple, that is that it became stronger/brighter than a rising on the skin. And it that was like white wool but became like the membrane/skin of an egg, that it is that the swelling/sore became a rising on the skin.

וכסיד ההיכל והשלג – meaning to say that it was like the lime of the Temple but now it became like snow.

רבי עקיבא אומר וכו' – And the Halakha is according to Rabbi Akiba.