If someone forgot to put on tefillin on Friday and only realized after he made early Shabbos, would he be permitted to put on tefillin before the sun sets?

The first question is, must one wear tefillin every day? The gemara [1] cites two reasons why we do not wear tefillin on Shabbos. R’ Akiva says that since tefillin serve as an אות that we are completely devoted to Hashem and Shabbos itself is an אות, it is unnecessary to have a second אות of tefillin on Shabbos. R’ Yose Hagelili understands based on the words מימים ימימה that one does not wear tefillin at night or on Shabbos and Yom Tov. From this gemara it seems that barring a specific exception one must wear tefillin every day. This appears to be the understanding of the Kesef Mishnah [2] and stated clearly by the Biur Halacha [3]. However, the Brisker Rav is cited by R’ Moshe Shternbuch [4] as arguing that fundamentally there is no Biblical obligation to wear tefillin every day. He argues that there is no inherent daily obligation as the mitzvah is a constant obligation and it is only due to our inability to stay focused that we wear Tefillin only during Shacharis [5].

While it is clear that one is not obligated to wear tefillin on Shabbos, it is unclear if it is prohibited to do so. The Shulchan Aruch, [6] following the Rosh [7] as well as the Zohar, [8] believes that it is prohibited to wear tefillin on Shabbos because it is disrespectful to the אות of Shabbos [9]. However, the Bach [10] understands from the Tur that while there is no obligation on Shabbos it is not forbidden [11]. Regarding nighttime, aside from the source of ימים ימימה the gemara mentions a practical reason to forbid wearing tefillin at night [12]. Tefillin demands focus on the mitzvah and that one remain in a proper state, and at night one is more likely to fall asleep and flatulate. It is for this reason that Chazal forbade one from putting on tefillin at night. The Rambam [13] assumes that tefillin may not be worn at night as he cites ימים ימימה, while the Shulchan Aruch [14] records the concern that one may fall asleep. The Terumas Hadeshen [15] addresses the question of one who davened Maariv prior to sunset only to realize that he hadn’t yet put on tefillin. He writes that one may not put on tefillin after Maariv as it would be תרתי דסתרי to wear tefillin, a daytime mitzvah after having davened Maariv. The Shulchan Aruch [16] codifies this psak. However, the Mishna Berura [17] quotes the Elya Rabah, [18] who disagrees and requires one to wear Tefillin at this time. He argues that because there is no inherent prohibition of wearing tefillin at night, and although one davened Maariv, there is no concern that he may fall asleep. Thus, he argues that in this situation one may wear tefillin after davening Maariv but omit the brachos. Can the same be said about wearing tefillin after one’s personal קבלת שבת?

The question of קבלת שבת when it precludes one from performing a mitzvah is discussed by the Taz [19] in Hilchos Rosh Hashanah. He recalls an instance where a small town had their shofar stolen on Wednesday Erev Rosh Hashanah and they dispatched a non-Jew to bring them another one. By the time the shofar arrived late Friday afternoon they had already accepted early Shabbos. The Taz argues that their acceptance of Shabbos constitutes a קבלה בטעות and it is not binding. If they had known that the shofar would arrive before Shabbos, they never would have accepted early Shabbos and for this reason it is permissible for them to blow shofar [20]. The Taz then pivots and argues that because blowing shofar on Shabbos is prohibited on a rabbinic level, the acceptance of Shabbos does not prevent blowing shofar. R’ Shlomo Zalman [21] cites this Taz as proof that one who forgot to put on tefillin before קבלת שבת may do so afterwards as it was a קבלה בטעות. Thus, if one procured tefillin only after קבלת שבת we can assume that it was a קבלה בטעות and he can subsequently wear tefillin. However, things are more complicated if he already davened Maariv and recited Kiddush. If you suppose that the acceptance of Shabbos was a “mistake” then one must contend with a possible ברכות לבטלה from Maariv and Kiddush. Because of this problem if one already davened Maariv and made Kiddush his acceptance of Shabbos can no longer be deemed a mistake, and he should not put on tefillin and in this situation we can assume the position of the Brisker Rav that there is no absolute obligation to wear tefillin every day.

[1] Eiruvin 96a.

[2] Yesodei Hatorah 5:1.

[3] 37:2 d.h. Mitvasan.

[4] Teshuvos V’Hanhagos 1:49.

[5] See Shulchan Aruch 37:2.

[6] 31:1.

[7] Hilchos Teffilin 16.

[8] Cited by the Beis Yosef 31:1.

[9] See Magen Avraham (1) who believes that one who wears tefillin on Shabbos with the intention to fulfill a mitzvah violates בל תוסיף.

[10] 31:1.

[11] This is the opinion of Tosfos (Beitzah 15a d.h. Hachi). See Biur HaGra 31:1 d.h Asur.

[12] Eiruvin 96a.

[13] Tefillin 4:10,11.

[14] 30:2.

[15] 2:121.

[16] 30:5.

[17] 30:17.

[18] 30:5.

[19] 600:2.

[20] See Levush (263:17).

[21] Halichos Shlomo Tefillah 4, footnote 17.