Frontlets

Frontlets (Hebrew totaphoth) appear in three passages of the Mosaic law: Exodus 13:16 and Deuteronomy 6:8 and 11:18. In each case, the command is to bind God's words "as a sign upon thine hand" and as "frontlets between thine eyes." In Jewish tradition, the literal interpretation of these commands produced the practice of phylacteries (tefillin) — small leather boxes containing four passages of Scripture (Exodus 13:1–10; 13:11–16; Deuteronomy 6:4–9; 11:13–21), strapped to the forehead and left arm during morning prayers by observant Jewish men.

Whether Moses intended the command literally or as a vivid metaphor for keeping the law constantly in one's thoughts and actions has been debated. Many scholars read the surrounding context — "thou shalt teach them diligently unto thy children...when thou sittest in thine house, and when thou walkest by the way" (Deuteronomy 6:7) — as indicating that the "frontlets" command is part of a cluster of metaphorical idioms for comprehensive devotion to the law, not just a prescription for literal objects. Jesus critiques the Pharisees for making their phylacteries "broad" for show (Matthew 23:5), indicating that the practice was well-established by the first century but susceptible to ostentation.