The Mordechai holds (see OC siman 13, MG"A) that a person is allowed to wear a 4 cornered garment on shabbos even if it is missing tzitzis. Since one is not allowed to tie tzitzis on shabbos, there is a ptur ones which exempts one from the mitzvah.
(The Mordechai seems to hold that ones is not a maaseh aveira with a ptur from onshim, but is not a maaseh aveira at all.)
Rav Noson Gestetner (in Maor haTorah) asks: the SA paskens (YD 120:16) that if you forgot to be toveil a kli before shabbos you should be makneh it to an aku"m and then borrow it back to use. According to the Mordechai, why is this necessary? Since you cannot be toveil a kli on shabbos, you should be exempt from the mitzvah based on the ptur of ones. Why is tevilas kelim any different than the case of tzitzis?
This is such a nice question that I'm going to leave it up as-is without answers or comments so it has time to marinate. Sometimes you need to pause to savor the "im tomar" before rushing to the "yesh lomar." Bli neder will come back to it.
Great question!
ReplyDeleteI think the simplest (non-fancy) answer is that tieing tzitzis is assur min hatorah, while toiveling a kli is only assur miderabbanan. So it's an ones mh"t for tiztzis, hence a ptur min hatorh, but for tvila it's only an ones miderabanan, but on a deoraysa level still chayav tvila, so it's still asur.
Of course this gets into the question of whether denim derabanan have a chalos mideoraysa, probably depends on Rambam/Ramban in sefer hamitzvos etc.
You hit the nail on the head of the direction he goes in, but in the end he rejects this answer because the issur of using a kli w/o tevilah is also only derabbaban (Biur Halacha in siman 323), so he argues that an issur derabbanan is enough of an ones to knock off a chiyuv derabbanan.
Delete>>>Of course this gets into the question of whether denim derabanan have a chalos mideoraysa, probably depends on Rambam/Ramban in sefer hamitzvos etc.
A nitpick -- you could argue that an issur derabbanan qualifies as ones without saying issurei derabbanan have a chalos d'orasysa. Maybe simply the practical fact that you can't do something is enough to meet the threshold of ones.
Thinking about it more, I think you are correct (and I would not consider this a nitpick at all) - an issur derabbanan should be considered an ones min hatorah, no less than any other practical non-halachic impediment to doing a mitzvah. I agree.
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