Phylactery

Phylacteries (Greek phylakteria, "safeguards"; Hebrew tefillin) are small leather boxes containing four passages of Scripture — Exodus 13:1–10, 13:11–16, Deuteronomy 6:4–9, and 11:13–21 — worn by Jewish men during weekday morning prayers. They are bound by leather straps: one on the forehead between the eyes, and one on the left arm near the heart, in literal obedience to the command of Deuteronomy 6:8: "You shall bind them as a sign on your hand, and they shall be as frontlets between your eyes."

The practice is ancient, attested by finds at Qumran (the Dead Sea Scrolls community). Jesus criticizes those who make their phylacteries broad for public display (Matt. 23:5), condemning ostentation rather than the practice itself. The theological purpose is to keep God's law continually before the mind and near the heart — a physical embodiment of the Shema's command to love God with the whole person.