With what does the Tamei Meis become purified?
Rashi: With the ashes 1 of the Parah Adumah.
With water sanctified with the ashes. Rashi said the ashes to explain "Hu Yischatei Bo" (which is masculine singular. Water is plural, and Parah is feminine. ? PF)
Having written that a Tamei Meis who is sprinkled on the third and seventh days is Tahor, why does the Torah need to add that if he isn't sprinkled ... he is Tamei? Why is it not self-understood?
Kidushin, 62a (citing R. Meir): Because if both sides of a stipulation - the positive and the negative - are not stated, like the stipulation of the B'nei Gad and the B'nei Reven, it does not take effect.
Oznayim la'Torah: Because, bearing in mind that ll other Tun'os become Tahor via Tevilah alone, we maight otherwise have thought that sprinkling with the Eifer ha'Parah is a Mitzvah, but is not crucial to the Taharah.
In Kidushin, 62a, the Gemara say that R. Chanina ben Gamliel, who extrapolates the positive from the negative, needs "ve'Im Lo Yischata", in case we say that it is a mere Mitzvah Lechatchilah to sprinkle on both days three and seven, but Bedi'eved one of them suffices. We already know this from "Chukah", which teaches that what is written is Me'akev?
Perhaps he holds like R. Yonason, who normally interprets 'Vav' to mean 'or'. Here, he agrees that one must sprinkle on both days, due to the repetition. 1 (PF)
However, the Gemara should have explained that he holds like R. Yonason. Perhaps this is why Moshav Zekenim left this question difficult! (PF).
