421. Black Box: The obligation to wear tefillin on the arm
Tie them as a sign on your arm… (Deuteronomy 6:8)
Tefillin are black leather boxes that contain certain Scriptural passages written on parchment. These are fastened to the head and to the arm by black leather straps. (In English, the word for tefillin is “phylacteries,” though this is a case where Americans need the Hebrew word to explain what the English word means.) The obligation to place tefillin on the head and on the arm are two separate mitzvos. Here, we deal with the tefillin shel yad, the one placed on the arm.
The tefillin of the arm contain four sections, two from parshas Bo (Exodus 13:2-10 and 11-6), one from parshas Va’eschanan (Deuteronomy 6:4-9, which includes the Shema), and one from parshas Eikev (Deuteronomy 11:13-21). The tefillin are tied to a person’s weaker arm, so most people (who are right-handed) wear them on the left arm. The box containing the parchment is placed adjacent to one’s heart.
The reason for this mitzvah is that it’s something like a spirituality antenna. Our souls are bogged down by the mundanity that surrounds them. The tefillin serve to amplify the spirituality in the atmosphere in order to reinvigorate our souls so that we will pursue holiness rather than solely physical pursuits.
This mitzvah applies to men in all times and places (though not on Shabbos and Yom Tov). It is discussed in the Talmud in tractate Menachos (34a-37b) and in Eiruvin (95a-97b). It is codified in the Shulchan Aruch in Orach Chaim 25. This mitzvah is #13 of the 248 positive mitzvos in the Rambam’s Sefer HaMitzvos and #8 of the 77 positive mitzvos that can be fulfilled today as listed in the Chofetz Chaim’s Sefer HaMitzvos HaKatzar.