Is a temporary craftsman's knot tied for the sake of a mitzvah permitted on Shabbat?
Synopsis
The Mechaber permits a temporary craftsman's knot for a mitzvah purpose (e.g., measuring a mikveh). The Beit Meir notes this is specifically the Rambam/Tur view, while Rashi, Tosafot, and the Bartenura hold that a forbidden knot remains forbidden even for a mitzvah.
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