Exodus 13:8-9
Exodus 13:8-9 AMP
You shall explain this to your son on that day, saying, ‘It is because of what the LORD did for me when I came out of Egypt.’ It shall serve as a sign to you on your hand (arm), and as a reminder on your forehead, so that the instruction (law) of the LORD may be in your mouth; for with a strong and powerful hand the LORD brought you out of Egypt.