and when Pharaoh refused to let us go, Adonai slew all the firstborn in the land of Egypt, both men and animals. So I sacrifice to Adonai all firstborn males, but I redeem the firstborn of my sons.’
So it came about at midnight that Adonai struck down all the firstborn in the land of Egypt, from the firstborn of Pharaoh sitting on his throne to the firstborn of the captive who was in the dungeon, and all the firstborn cattle.
A firstborn donkey you are to redeem with a lamb, but if you do not redeem it, then you are to break its neck. You must redeem all your firstborn sons. No one should appear before Me empty-handed.
The first offspring of the womb from all flesh, whether human or animal, offered to Adonai, is yours. However, you are to redeem the firstborn of man and the firstborn of unclean animals.