Tying a knot is permited if it is meant to be only temporary, and is not a professional knot. The Rama 317:1 brings two opinions as to what is considered to be temporarary. One opinion says that the knot must be intended to be untied within 24 hours, while the other opinion says 7 days. The Mishna Berura 317:29 sides with the first opinion. Therefore, any not knot which is normally tied for longer than one day, should not be made. For example, the “gartel” around the Sefer Torah should not be tied after mincha on Shabbos. Since the Torah will not be used until Monday, the knot is not considered temporary.

Rabbi Tzvi Aryeh Hyman, Mir Yeshiva
If you have any questions or comments please send them to:
[email protected]