Exodus 13:11-15

“Now when the LORD brings you to the land of the Canaanite, as He swore to you and to your fathers, and gives it to you, you shall devote to the LORD the first offspring of every womb, and the first offspring of every beast that you own; the males belong to the LORD. But every first offspring of a donkey you shall redeem with a lamb, but if you do not redeem it, then you shall break its neck; and every firstborn of man among your sons you shall redeem. And it shall be when your son asks you in time to come, saying, ‘What is this?’ then you shall say to him, ‘With a powerful hand the LORD brought us out of Egypt, from the house of slavery. It came about, when Pharaoh was stubborn about letting us go, that the LORD killed every firstborn in the land of Egypt, both the firstborn of man and the firstborn of beast. Therefore, I sacrifice to the LORD the males, the first offspring of every womb, but every firstborn of my sons I redeem.’