Bible Dictionary
Phylactery
A phylactery was a leather case containing passages from the Law and bound to the arm or forehead. The practice arose from a literal application of passages about keeping God’s words as a sign, and Jesus rebuked its ostentatious use.
Biblical Usage
The word occurs in Matthew 23:5, where Jesus rebuked the Pharisees for making their phylacteries broad so that their religious devotion would be seen by others. The supplied material also connects the practice with the Old Testament passages translated “frontlets.”