Borrowing Tefillin — Eruvin 97a

Borrowing Tefillin — Eruvin 97a


תלמוד בבלי מסכת עירובין דף צז/א
אחד חדשות ואחד ישנות דברי רבי מאיר רבי יהודה אוסר בחדשות ומתיר בישנות אלמא מר סבר טרח איניש ומר סבר לא טרח איניש:... וליענבינהו מיענב אמר רב חסדא זאת אומרת עניבה פסולה בתפילין אביי אמר רבי יהודה לטעמיה דאמר עניבה קשירה מעלייתא היא טעמא דעניבה קשירה מעלייתא היא הא לאו הכי עניב להו והאמר רב יהודה בריה דרב שמואל בר שילת משמיה דרב קשר של תפילין הלכה למשה מסיני הוא

The Avnei Nezer (Orach Chaim 183:5) writes, that since there emerges from our Gemara the law that the knot of tefillin must be a permanent knot — kesher shel kayama — (see Tosafos here d.h. Amar Rav Chisda; and to Menachos 35b d.h. MeShe'as Hanachah), there is a problem that may frequently arise in borrowing tefillin from another person: Often the person who borrows the tefillin must change their size in order that they should fit, and he therefore has to undo the knot and re-tie it to size. Then, however, when the owner receives the tefillin back, he will necessarily re-tie the knot to his size. If so, frequently the knot that the borrower tied in the tefillin does not last for twenty-four hours – the criterion for a permanent knot.

Why do we not conduct ourselves according to this stringency of the Avnei Nezer? R' Shlomo Zalman Auerbach (Teshuvos Minchas Shlomo, Tinyana 1:3) writes that the reason is because it is reasonable to distinguish between a knot that is made with the deliberate intent to undo it (such as is the case according to Rabbeinu Eliyahu, who holds that each day when you take off your tefillin you must undo the knot, and tie it anew the next day — see Tosafos ibid.); and a case in which as far as you (the borrower) are concerned, the knot can remain in place forever,