Exodus 13:9, 16

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.

So it shall serve as a sign and a reminder on your [left] hand (arm) and as frontlets between your eyes, for by a strong and powerful hand the LORD brought us out of Egypt.”