Exodus 13:14-16 Amplified Bible, Classic Edition (AMPC)

¹⁴ And when, in time to come, your son asks you, What does this mean? You shall say to him, By strength of hand the Lord brought us out from Egypt, from the house of bondage and bondmen.

¹⁵ For when Pharaoh stubbornly refused to let us go, the Lord slew all the firstborn in the land of Egypt, both the firstborn of man and of livestock. Therefore I sacrifice to the Lord all the males that first open the womb; but all the firstborn of my sons I redeem.

¹⁶ And it shall be as a reminder upon your hand or as frontlets between your eyes, for by a strong hand the Lord brought us out of Egypt.