The Ramban (1194-1270) wrote a fabulous book on Jewish thought. I think it’s relatively obscure, but it’s one of my all-time favorites. Referred to as “Derashah” or “Drashas HaRamban,” the book was originally just that: an extended sermon given before the King of Castile.
This work is written in a style similar to Moreh Nevuchim (“A Guide for the Perplexed”) by his predecessor, the Rambam (Maimonides), but seems to be less influenced by the philosophical trends of the Rambam’s period. The Ramban touches on a wide range of subjects, from Creation to the Giving of the Torah to Bible codes (yes, he noticed without a computer) to prophecy, and many other topics.
In his discussion of miracles, he makes an interesting remark on a number of mitzvahs, including the mitzvah of tefillin.
The Ramban writes (starting on p. 50 in my edition) that the kind of major, dramatic miracles that take place at certain junctures in history do not occur in every generation for two reasons: because some generations are unworthy or because in some generations there is no need for miracles.
However, Hashem commanded us to keep a remembrance of these miracles for all time and the Torah is very strict regarding this requirement. As evidence, he points to one of the most salient examples, the Pesach offering, noting that one who fails to fulfill this mitzvah incurs an unusually harsh punishment, kares, which is normally reserved for serious violations of negative mitzvahs, not for neglecting to do a positive mitzvah.
The Ramban goes on to point out several day-to-day mitzvahs – including tefillin – whose essential purpose is to keep in mind miracles that transpired long ago.
One excerpt from the passage written on tefillin parchments reads as follows:
And it [tefillin] shall be for a sign for you upon your hand, and as a memorial between your eyes, that the law of the Lord may be in your mouth; for with a strong hand has the Lord brought you out of Egypt. You shall therefore keep this ordinance in its season from year to year.
When we lay tefillin, explains the Ramban, we place a written chronicle of the Exodus “on the arm, opposite the heart, and on the head, opposite the brain, which is the seat of the soul.”
The Ramban also wrote a famous commentary on the Five Books of Moses, while living in Eretz Yisrael after he was banished from his native Spain. On Shemos 13:16 he launches into a long discussion of the meaning of tefillin.
On the words in verse 9, ul’zikaron bein einecha (“as a memorial between your eyes”) refers to the position of the tefillin on the head, “which is the initial point of memory and the base for images after the are no longer before him,” adding that the tefillin knot rests on the back of the head near the part of the brain that preserves memory.
The Ramban notes that other mitzvahs, in addition to tefillin, are a memorial to the Exodus, in essence to silence heretics, because by recalling how Hashem brought us out from Egypt with an outstretched Hand, we are pointing to His renewal of Creation, our knowledge of Him and His active involvement in worldly affairs.
To read more of the Ramban’s remarks on tefillin,
the Israel Koschitzky Virtual Beit Medrash (Yeshivat Har Etzion)
has an extended article on the Ramban and tefillin.