Exodus 13:11-16 - The Feast Of Unleavened Bread

¹¹ "When the LORD brings you to the land of the Canaanite and gives it to you, just as he promised you and your ancestors, ¹² you are to dedicate to the LORD everything that first opens the womb. All the firstborn males of your livestock belong to the LORD. ¹³ You are to redeem every firstborn donkey with a lamb, and if you don't redeem it, you are to break its neck. You are to redeem every firstborn among your sons.

¹⁴ Then when your child asks you in the future, "What is this?', you are to say to him, "The LORD brought us out of Egypt, from the house of bondage with a strong show of force. ¹⁵ And when Pharaoh stubbornly refused to let us go, the LORD killed every firstborn in the land of Egypt, from the firstborn of humans to the firstborn of animals. Therefore, I sacrifice to the LORD every male that first opens the womb, but I redeem every firstborn of my sons. ¹⁶ It is to be a sign on your hand and an emblem on your forehead, because the LORD brought us out of Egypt with a strong show of force.'"