Phylacteries were small leather boxes containing parchment scrolls inscribed with key Torah texts, worn by Jewish men during prayer as a literal observance of Deuteronomy 6:8 and Exodus 13:9. One box was bound to the forehead and another to the left arm. Jesus criticized the scribes and Pharisees for making their phylacteries conspicuously wide as a display of piety. The Greek term reflects the word's original sense as an 'amulet' or 'safeguard,' though in Jewish practice these were sacred reminders of God's law rather than magical charms.