Negaim 4:11-5:1

Negaim 4:11

If a white spot the size of a split bean had nothing in it, and then a white spot the size of half a split bean with two hairs in it appeared, it is confirmed as unclean. This is because our Sages said that if the white spot preceded the white hair, one is ritually unclean; if the white hair preceded the white spot, he is ritually clean. If it is doubtful which came first, one is ritually unclean, though Rabbi Yehoshua balked at this ruling.

Negaim 5:1

All doubtful negas are ritually clean except for the case in the previous mishna and one other, i.e., if one had a white spot the size of a split bean and he was quarantined, and by the end of the week it was as big as a sela. If it’s doubtful whether this is the original nega or whether another nega took its place, it must be ruled ritually unclean.