Do Not Add To Them! ‘Shabbos is not a Time for Tefillin’ (Shabbos 61a)
The Gemara cites a machlokes about wearing tefillin on Shabbos. As we all know, the accepted custom is not to wear tefillin on Shabbos. However, what is not clear is whether it is simply unnecessary to wear tefillin on Shabbos or actually forbidden.
Elsewhere, the Gemara cites two reasons for why tefillin are not worn on Shabbos (Eruvin 96a; Menachos 36b). One reason is based on the pasuk in parshas Bo, “They shall be for you as a sign upon your arm” (Shemos 13:9). The Gemara explains that tefillin must be worn as a sign on weekdays. Shabbos, however, is also referred to as a “sign” in the Torah; therefore tefillin are not worn as they are not necessary.
The Maharsha explains that according to all opinions this is the primary reason (see Aruch Hashulchan 30:3). The Rishonim (Smag, positive commandment 3; Rabbeinu Bachaye, parshas Lech Lecha) add that on weekdays, we have two “witnesses” who testify that we are servants of Hashem: bris milah, the sign of the covenant that Hashem made with us, as well as tefillin, which serve as a sign of our servitude to Hashem. Shabbos is also a sign of the unity of Hashem and the Jewish people, as the pasuk says, “It is a sign between Me and you,” (Shemos, 31:13).
No Bris Milah, No Tefillin On Shabbos
The Terumas Hadeshen (Teshuvos 2:108, cited in Birkei Yosef 31) asks whether an uncircumcised Jew must wear tefillin on Shabbos. Halacha dictates that if two brothers die as a result of bris milah, it is forbidden to circumcise a third brother. On a regular weekday, this third brother has only one “witness,” that of tefillin. On Shabbos, he would have an opportunity to have two: Shabbos and tefillin.
The Terumas Hadeshen states that this Jew should nevertheless not wear tefillin on Shabbos. He explains that the Smag drew the metaphor of two witnesses as an aggadah. He never intended it to be the basis for halachic conclusions. Therefore, an uncircumcised Jew is also exempt from tefillin on Shabbos.
The Radvaz (Teshuvos 2:334) adds that even according to the metaphor of the two witnesses, an uncircumcised Jew is exempt from tefillin on Shabbos. Why? The Gemara (Nedarim 31b) states that if a person makes a neder not to let uncircumcised people benefit from his possessions, he is forbidden to allow benefit to a gentile but he may allow benefit to an uncircumcised Jew. This is because the very mitzvah to perform bris milah, even if one is unable to, is a sign of the covenant between Hashem and the Jewish people.
Interestingly, the Rokeach (30, cited in Aruch HaShulchan) explains that bris milah alone is an insufficient sign since it testifies only to the covenant Hashem forged with us. Tefillin testify also to yetzias Mitzraim, as does Shabbos. Therefore, the sign of Shabbos can take the place of tefillin.
The Mechaber And The Zohar
The Mechaber (O.C. 31:1) rules quite clearly that it is forbidden to wear tefillin on Shabbos. “Shabbos is itself a sign,” the Mechaber explains. “By wearing a different sign, one denigrates the sign of Shabbos.” The Vilna Gaon (ibid.) points out that there is no source for this ruling in the Rambam or Tur. Rather, the Mechaber draws this ruling from the Midrash Ne’elam, the Zohar’s commentary on Shir HaShirim, which is cited at length in the Beis Yosef. This is one of the very few halachos that the Mechaber draws from the Zohar rather than Shas.
Tefillin On Shabbos Is Bal Tosif
According to the Mechaber’s explanation, wearing tefillin on Shabbos is not a Torah prohibition (see Aruch Hashulchan; Levush, ibid). However, the Magen Avraham (ibid.) cites the Rashba that wearing tefillin on Shabbos is a violation of bal tosif, the prohibition against adding mitzvos.
The Magen Avraham adds that this applies only if a person wears tefillin with the intention to fulfill a mitzvah. If he puts them on without this intention, he is not violating bal tosif (see Eruvin 96a). Nor is he demeaning the sign of Shabbos since he does not intend to wear them as a sign.