Exodus 13:13-15

New Revised Standard Version, Anglicised Catholic Edition

¹³ But every firstborn donkey you shall redeem with a sheep; if you do not redeem it, you must break its neck. Every firstborn male among your children you shall redeem. ¹⁴ When in the future your child asks you, “What does this mean?” you shall answer, “By strength of hand the Lord brought us out of Egypt, from the house of slavery. ¹⁵ When Pharaoh stubbornly refused to let us go, the Lord killed all the firstborn in the land of Egypt, from human firstborn to the firstborn of animals. Therefore I sacrifice to the Lord every male that first opens the womb, but every firstborn of my sons I redeem.”