Exodus 13:13-15

Living Bible

¹³ A firstborn donkey may be purchased back from the Lord in exchange for a lamb or baby goat; but if you decide not to trade, the donkey shall be killed. However, you must buy back your firstborn sons.

¹⁴ “And in the future, when your children ask you, ‘What is this all about?’ you shall tell them, ‘With mighty miracles Jehovah brought us out of Egypt from our slavery. ¹⁵ Pharaoh wouldn’t let us go, so Jehovah killed all the firstborn males throughout the land of Egypt, both of men and animals; that is why we now give all the firstborn males to the Lord—except that all the eldest sons are always bought back.’