Shabbat Parashat Ki Teitzei 5771

Ask the Rabbi: Tefillin for One Who Writes With His Left Hand

Question: My son writes with his left hand (he can write slowly and neatly with his right) but does everything else better with his right. Should he use righty or lefty tefillin?


Answer: There are three sources for the rule that a righty lays tefillin on his left hand (Menachot 36b-37a). Tanna Kamma says the word “yadchah” (where one fastens the tefillin) means the left arm. R. Natan learns from proximity in the Torah that the hand one uses to write a mezuzah he uses to fasten tefillin. A person who writes with his right hand should thus use that hand to fasten the tefillin onto his left arm. R. Ashi learns from the extra letter “ä” “yadchah” (Shemot 13:16) that tefillin go on the yad kehah (weak hand). A lefty, who writes with his left and whose weak hand is his right, thus lays tefillin on his right arm (Shulchan Aruch, Orach Chayim 27:6).

How do we view one who writes with one hand but does most activities with the other? The Sefer Haterumah says to lay the tefillin on the overall weaker hand, without special emphasis on writing. R. Yechiel of Paris says that one who writes with his right hand lays on his left arm even if he does everything else with his left (see Tur, Orach Chayim 27). The opinions in Rishonim are apparently based on the different sources in the gemara above. The Shulchan Aruch (ibid.) and Rama favor R. Yechiel’s opinion, to follow one’s writing. Thus, your son’s case seems to depend on this machloket, and at first glance he should lay tefillin on his right arm.

However, some major poskim question the Shulchan Aruch’s and Rama’s ruling. The Gra (OC 27) demonstrates that Rav Ashi’s opinion is more accepted and that we thus should put tefillin on the overall weaker hand. Furthermore, the Bach (OC 27) argues on the Shulchan Aruch’s understanding of R. Yechiel. He says that R. Yechiel accepted both the source of “writing-fastening” and that of “the weak hand” and, only when one is a lefty in both regards does he lay on the right. Similarly, R. Moshe Feinstein (Igrot Moshe OC IV, 11; see Tosafot, Menachot 37a) understands that one who writes with one hand but does most work with the other lays on the left arm because he is deemed ambidextrous (sholet b'shtei yadav).

Let us view the parameters of sholet b'shtei yadav. The gemara (Menachot 37a) brings a contradiction between sources on whether an iter (lefty) lays on his right or left and answers that it is an ambidextrous who lays on his left. But if he is ambidextrous, why is he called an iter? The simple answer is that as long as both hands are functional, even if he favors his left, he puts on tefillin like most people, who are righties. However, Rashi (ad loc.) says that it is referring to one who is equally strong in both hands, as do the Aruch Hashulchan (OC 27:15) and Mishna Berura (27:25). Your son’s situation of writing slowly but neatly does not seem to make him ambidextrous enough regarding writing to remove him from serious doubt. Since we bless him to put on tefillin tens of thousands of times, we would like to extricate him from doubt.

The best suggestion, which is probably practical, is for your son to practice writing with his right hand until he can write comfortably with it on occasion throughout his life (see Shulchan Aruch Harav, OC 27:9; Shevet Halevi IV, 6). Although the Beit Yosef (OC 27) cites a machloket on whether a learned proficiency counts, the more accepted opinion is that it does (see Mishna Berura 27:23; Yabia Omer, VI, OC 2). It is logical that while to be ambidextrous regarding strength, one needs equality because “the weak hand” is a relative term, regarding writing, the tefillin only have to be fastened by a hand that can do legitimate writing (see Shabbat 103a and Shoel U’meishiv II, II:58). Thus, your son only has to write reasonably with his right hand to justify putting tefillin on his left. (Note also that there is a minority opinion that even lefties can/should put tefillin on their left arm (see Sha’arei Teshuva 27:11)).

If this is not working or if it is overly stressful for your son, please get back to us.

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