Overview
Phylacteries (Hebrew: tefillin) were leather boxes containing written portions of Scripture, worn during prayer as a physical reminder to keep God's commands always before the mind and heart. They developed from the literal interpretation of Deuteronomy 6:8 and Exodus 13:16, though the practice evolved beyond the original intent. Jesus confronted the religious leaders who enlarged their phylacteries to draw attention to themselves rather than genuine devotion to God's law.
Key Scriptures
"And these words that I command you today shall be on your heart" (Deuteronomy 6:6, ESV). "You shall bind them as a sign on your hand, and they shall be as frontlets between your eyes" (Deuteronomy 6:8, ESV). "They do all their deeds to be seen by others. For they make their phylacteries broad and their fringes long" (Matthew 23:5, ESV).
Application
Guard against religious externalism; ensure your outward expressions of faith reflect genuine inward devotion to God's Word and commandments.