Rav Menachem Zemba was one of the greatest Torah scholars in pre-war Poland and a Gerrer Chossid. He participated in the Warsaw ghetto uprising and was killed by the Nazis on Seder night in 1942. On Erev Pesach he wrote down a question on a piece of paper that was found afterwards. The paper was ripped and only the question was recorded. This was the question Rav Menachem Zemba was pondering before he was murdered.
The Rambam believed that tzaraas exists even in our day and age. Based on this assumption the Rambam wonders why we don't have the metzora go through the purification process after the tzaraas disappears. In other words he should shave off all of his hair, have a kohen slaughter a bird and send one away, and sprinkle on him seven times . There is also a mitzva to bring korbanos which cannot be done today, but the korbanos are not absolutely necessary ["me'akeiv"] for the purification of the metzora - he can be purified without them.
The Rambam's answer is very interesting. Part of the purification process is shaving off all of his hair. That is a transgression of the sin of shaving off a person's sideburns [lo takifu peas roshchem]. Normally it is overriden by the mitzva of purification as per the rule "aseh docheh lo taaseh" - a positive mitzva pushes a side a negative mitzva [as the mitzva of tzitzis pushes aside the sin of wearing shatnez]. But this rule is only operative if the mitzva is done in its entirety. We need a complete "set" in order to push away a lo taaseh. In our situation, even though the korbanos are not meákev, since the mitzva cannot be performed in the ideal way [due to the absence of the beis hamikdash], the prohibition of shaving off one's sideburns remains in force. That is why a metzora doesn't go through the purification process in our day and age. [The Tolna Rebbe Shlita asked that according to this explanation a woman should have no problem doing the purification because she isn't prohibited form shaving off her sideburns. Yet we don't see women metzora's being purified.]
Asked Rav Menachem Zemba in 1942: The mishna in Menachos teaches that according to Rebbe Yishmael the mitzva of wearing tzitzis is composed of four different mitzvos, one mitzva for each corner. The Chachomim argued that all four corners constitute only one mitzva. The gemara wonders what the practical difference [nafka mina] between the two opinions might be. The gemara answers very simply: The garment is made of wool, the strings are linen and the person only has strings for one corner. If all four corners are one mitzva then it would be forbidden to hang the linen strings on one corner. That is the opinion of the Chachomim. But Rebbe Yishmael holds that that every corner is a distinct, separate mitzva and it would hence be permitted to tie one corner with linen strings despite the fact that the garment is made of wool and the mixture would constitute shatnez because the lone corner with strings is a separate mitzva.
Now Rav Zemba dropped his bomb. According to Rebbe Yishmael a single corner with tzitzis is indeed a mitzva but where is the "set"?! The Rambam established that in order for a mitzva to override an aveirah the mitzva needs to be performed in the most complete way with ALL of its components [even those that are not critical]. Of course even Rebbe Yishmael agrees that ideally tzitzis should have strings on all four corners. So in order to permit the aveirah of shatnez we require a complete mitzva of strings on all four corners, just as we require the bringing of korbanos in order to override the aveirah of shaving off the sideburns of a metzora?!
This beautiful, thought provoking question was published in the sefer "Chiddushei Rebbe Menachem Zemba" but to our great dismay the holy tzaddik took his answer with him to the heavens. Maybe you can help?
