Their phylacteries - The word “phylactery” comes from a word signifying to keep, preserve, or guard. The name was given because phylacteries were worn as amulets or charms, and were supposed to defend or preserve those who wore them from evil. They were small slips of parchment or vellum, on which were written certain portions of the Old Testament. The practice of using phylacteries was founded on a literal interpretation of that passage where God commands the Hebrews to have the law as a sign on their foreheads, and as frontlets between their eyes, Exodus 13:16; compare Proverbs 3:1, Proverbs 3:3; Proverbs 6:21. One kind of phylactery was called a “frontlet,” and was composed of four pieces of parchment, on the first of which was written Exodus 12:2-10; on the second, Exodus 13:11-21; on the third, Deuteronomy 6:4-9; and on the fourth, Deuteronomy 11:18-21. These pieces of parchment, thus inscribed, they enclosed in a piece of tough skin, making a square, on one side of which is placed the Hebrew letter shin (שׁ sh) and bound them round their foreheads with a thong or ribbon when they went to the synagogue. Some wore them evening and morning; others only at the morning prayer.
As the token upon the hand was required, as well as the frontlets between the eyes Exodus 13:16, the Jews made two rolls of parchment, written in square letters, with an ink made on purpose, and with much care. They were rolled up to a point, and enclosed in a sort of case of black calf-skin. They were put upon a square bit of the same leather, whence hung a thong of the same, of about a finger in breadth, and about 2 feet long. These rolls were placed at the bending of the left arm, and after one end of the thong had been made into a little knot in the form of the Hebrew letter yod (י y), it was wound about the arm in a spiral line, which ended at the top of the middle finger. The Pharisees enlarged them, or made them wider than other people, either that they might make the letters larger or write more on them, to show, as they supposed, that they had special reverence for the law.
Enlarge the borders of their garments - This refers to the loose threads which were attached to the borders of the outer garment as a fringe. This fringe was commanded in order to distinguish them from ether nations, and that they might remember to keep the commandments of God, Numbers 15:38-40; Deuteronomy 22:12. The Pharisees made them broader than other people wore them, to show that they had special respect for the law.