Exodus 13:14-16

141And it shall be when your son asks you in time to come, saying, ‘What is this?’ then you shall say to him, ‘2With 3a powerful hand the Lord brought us out of Egypt, from the house of 4slavery. 15And it came about, when Pharaoh was stubborn about letting us go, that the 5Lord put to death every firstborn in the land of Egypt, from human firstborns to animal firstborns. Therefore, I sacrifice to the Lord the males, every firstborn of a womb, but every firstborn of my sons I redeem.’ 16So 6it shall 7serve as a sign on your hand and as 8phylacteries 9on your forehead, for with 10a powerful hand the Lord brought us out of Egypt.”