And it shall be for a sign unto thee upon thy hand, and for a memorial between thine eyes. There can be no doubt that the Jewish system of tephillin, or "phylacteries," grew mainly out of this passage, and was intended as a fulfilment of the commands contained in it.
The tephillin were strips of parchment with passages of Scripture written upon them and deposited in small boxes, which were fastened by a strap either to the left arm, or across the forehead. The modern Jews argue that they were what Moses here intended, and that their employment began from this time.
Some Christian commentators agree with them. But the great majority argue, from supposed probability and from the entire absence of any reference to the actual wearing of tephillin in the Old Testament, that the custom must be, comparatively speaking, a modern one.
It is generally supposed to have originated, with other superstitious practices, in the time of the Babylonish captivity. Those who take this view regard the words of Moses in the present passage as merely metaphorical, and compare them with Proverbs 3:3; Proverbs 6:21; Proverbs 7:3.
Kalisch, however, observes with reason, that if the injunction to write passages of the Law on the door-posts of their houses (Deuteronomy 6:9; Deuteronomy 11:20) was intended to be understood literally, and was literally carried out (Isaiah 57:8), the commands with respect to tephillin, which are coupled with them (Deuteronomy 6:8; Deuteronomy 11:18) must have been similarly intended.
And probability, which is said to be against the Mosaic origin of tephillin, may perhaps rather be urged in its favour. The Egyptian practice Of wearing as amulets "forms of words written on folds of papyrus tightly rolled up and sewn in linen" is well attested.
Would it not be in harmony with the general character of his legislation, that Moses should adopt and regulate the custom, employing it to do honour to the Law and keep it in remembrance, without perhaps purging it wholly from superstitious ideas?
Moses allowed the Israelites in many things "for the hardness of their hearts," content if he could introduce some improvement without insisting at once on an impracticable perfection. That the law of the Lord may be in thy month.
The Israelites are instructed from the first, that the tephillin are to be a means to an end; and that the end is to be the retention of God's law in their recollection—" in their mouth," and therefore in their heart, since "out of the abundance of the heart the mouth speaketh."