פירוש על נגעים 4:10

בהרת כגריס ופשתה כגריס – we are speaking that it spread after the clearance/release [from impurity].

A bright spot the size of a split bean spread to the extent of a split bean, and in the spreading there appeared quick flesh or white hair, while the original spot disappeared: Rabbi Akiva says: it is unclean. But the sages say: it must be inspected as a new one. This is the last of the debates between Rabbi Akiva and the sages on this subject. The nega starts out the size of a split bean and then spreads again the size of a split bean. In the spreading there appears quick flesh or white hair. Had these appeared in the original nega, they would be a sign of impurity. However, the original spot also disappears. Rabbi Akiva is again consistent and holds that we consider this spreading to be part of the original nega, and therefore he says that he is impure. The other sages say that since the original nega is gone, he must begin the process over again. We should note that in this case, since there is a white hair or quick flesh in the nega, he will immediately be pronounced impure by the priest.

ר' עקיבא מטמא – for there is here a plague and the sign of defilement with it.

A bright spot the size of half a split bean with nothing in it, and then there appeared a bright spot the size of half a split bean and with one hair, this is to be isolated. The original bright spot is smaller than a split bean and does not have a white hair in it. Then a second bright spot appears with a white hair. We now have one full bright spot the size of a split bean, but since there is only one hair, the person is isolated and not deemed impure.

תיראה בתחלה – for even though that it should be examined anew, the Kohen should also declare it impure immediately. And the quick flesh and white hair defile at the beginning, nevertheless, the practical difference is that according to the Rabbis, he needs to bring a sacrifice for each and every one, but according to Rabbi Akiba it is considered like the first plague, and when it (i.e., the plague) falls away, he brings one sacrifice. And in all of these where Rabbi Akiba and the Sages disagree in our Mishnah, the Halakha is according to the Sages.

A bright spot the size of half a split bean with one hair and then there appeared another spot of the size of a half a split bean with one hair, this is to be isolated. In order for the white hair to be a sign of impurity, it must come out of a bright spot the size of a split bean. Although there are two white hairs in this bright spot, each came out of a bright spot less than the size of a split bean. Therefore, the two white hairs don't count as signs of impurity.

ואין בה כלום – it has no white hair.

A bright spot the size of half a split bean with two hairs and another spot of the size of half a split bean appeared with one hair, this is to be isolated. In this case, there are two white hairs in one bright spot, but it is only the size of half a split bean. As we saw before, for the white hairs to be a sign of impurity, they must come out of a bright spot the size of a split bean.

ובה שערה אחת ונולדה בהרת וכו' הרי זו להסגיר – and even though the bright white spot in the flesh like a Cilician bean came first to the last hair, since it didn’t come before the first [hair], it has no effect, for we require that the bright white spot in the flesh precedes like a split Ciliican bean to the two hairs.

בהרת כחצי גריס ובה שתי שערות וכו' הרי זו להסגיר – and even though the one-half Cilician bean preceded the two hairs, it has no effect until the full split Cilician bean precedes the two hairs.