Exodus 13:14-16

14And it shall be when thy son asketh thee in time to come, saying, What is this? that thou shalt say unto him, By strength of hand Yhwh brought us out from Egypt, from the house of bondage:1 15And it came to pass, when Pharaoh stubbornly refused to let us go, that Yhwh slew all the firstborn in the land of Egypt, both the firstborn of man, and the firstborn of beast: therefore I sacrifice to Yhwh all that openeth the matrix, being males; but all the firstborn of my children I redeem. 16And it shall be for a token upon thine hand, and for frontlets between thine eyes: for by strength of hand Yhwh brought us forth out of Egypt.