(Exodus 13:16; 6:8; 11:18; Matthew 23:5) These "frontlets" or "phylacteries" were strips of parchment, on which were written four passages of Scripture, (Exodus 13:2-10,11-17; 6:4-9,13-23) in an ink prepared for the purpose. They were then rolled up in a case of black calfskin, which was attached to a stiffer piece of leather, having a thong one finger broad and one and a half cubits long. They were placed at the bend of the left arm. Those worn on the forehead were written on four strips of parchment, and put into four little cells within a square case on which the letter was written. The square had two thongs, on which Hebrew letters were inscribed. That phylacteries were used as amulets is certain, and was very natural. The expression "they make broad their phylacteries," (Matthew 23:5) refers not so much to the phylactery itself, which seems to have been of a prescribed breadth, as to the case in which the parchment was kept, which the Pharisees, among their other pretentious customs, (Mark 7:3,4; Luke 5:33) etc., made as conspicuous as they could. It is said that the Pharisees wore them always, whereas the common people only used them at prayers.

The God of the Rain
... my words for a sign upon your hands, and they shall be as frontlets between your ...
and wrists, and the hems of their robes, enlarging their phylacteries, as our ...
/.../kingsley/the gospel of the pentateuch/sermon xvii the god of.htm

Matt. xxiii. 1-3.
... from their hands (wherefore also He said, "They shall be immoveable in thine eyes"),
[2661] which they called phylacteries; as many ... AV "as frontlets between.". ...
/.../homilies on the gospel of saint matthew/homily lxxii matt xxiii 1-3.htm

Woes on the Pharisees
... them for a sign upon thine hand, and they shall be as frontlets between thine ... they
do for to be seen of men: they make broad their phylacteries, and enlarge ...
//christianbookshelf.org/white/the desire of ages/chapter 67 woes on the.htm