15 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.
15
When Pharaoh stubbornly refused to let us go, the LORD killed the firstborn of both people and animals in Egypt. This is why I sacrifice to the LORD the first male offspring of every womb and redeem each of my firstborn sons.’