Thematic Bible: Consecration of the firstborn

And it shall be when thy son asketh thee in time to come, saying, What is this? that thou shalt say to him, By strength of hand the LORD brought us out from Egypt, from the house of bondage: And it came to pass, when Pharaoh would hardly let us go, that the LORD slew all the first-born in the land of Egypt, both the first-born of man, and the first-born of beasts: therefore I sacrifice to the LORD all that openeth the matrix, being males; but all the first-born of my children I redeem. And it shall be for a token upon thy hand, and for frontlets between thy eyes: for by strength of hand the LORD brought us forth out of Egypt.