Exodus 13:9

The celebration of this feast shall be to thee instead of a mark which a man makes, or a ring, or any thing else which he puts upon his hand or arm, to bring any thing to his remembrance; for such things his eye is most frequently fixed upon. Compare Song of Solomon 8:6 Isaiah 49:16 Jeremiah 22:24 Haggai 2:23. A memorial between thine eyes; instead of any monument or memorial, which is placed between, and therefore directly before a man's eyes, which he can scarcely overlook, and therefore must needs bring to remembrance the thing which he would not forget. Such proverbial phrases are usual in Scripture, as Deuteronomy 6:8 Proverbs 3:3, Proverbs 6:21 7:3; and are not to be understood literally, as the superstitious Jews understood them, who hence derive their custom of wearing scrolls of parchment upon their foreheads, and arms, and garments, which they call phylacteries, wherein they wrote certain portions of Scripture. But they might as well have added parcels of God's law to be kept in their mouths, because it follows, that the Lord's law may be in thy mouth; from whence we may better infer that neither mouth, nor hand, nor eyes are to be properly understood, for then, it had been an improper method to fasten a parchment between their eyes, that it might be in their mouths; but figuratively, as they are commonly understood in Scripture.