Exodus 13:1-16 ESV
The LORD said to Moses, “Consecrate to me all the firstborn. Whatever is the first to open the womb among the people of Israel, both of man and of beast, is mine.”
Then Moses said to the people, “Remember this day in which you came out from Egypt, out of the house of slavery, for by a strong hand the LORD brought you out from this place. No leavened bread shall be eaten. Today, in the month of Abib, you are going out. And when the LORD brings you into the land of the Canaanites, the Hittites, the Amorites, the Hivites, and the Jebusites, which he swore to your fathers to give you, a land flowing with milk and honey, you shall keep this service in this month. Seven days you shall eat unleavened bread, and on the seventh day there shall be a feast to the LORD. Unleavened bread shall be eaten for seven days; no leavened bread shall be seen with you, and no leaven shall be seen with you in all your territory. You shall tell your son on that day, ‘It is because of what the LORD did for me when I came out of Egypt.’ And it shall be to you as a sign on your hand and as a memorial between your eyes, that the law of the LORD may be in your mouth. For with a strong hand the LORD has brought you out of Egypt. You shall therefore keep this statute at its appointed time from year to year.
“When the LORD brings you into the land of the Canaanites, as he swore to you and your fathers, and shall give it to you, you shall set apart to the LORD all that first opens the womb. All the firstborn of your animals that are males shall be the LORD’s. Every firstborn of a donkey you shall redeem with a lamb, or if you will not redeem it you shall break its neck. Every firstborn of man among your sons you shall redeem. And when in time to come your son asks you, ‘What does this mean?’ you shall say to him, ‘By a strong hand the LORD brought us out of Egypt, from the house of slavery. For when Pharaoh stubbornly refused to let us go, the LORD killed all the firstborn in the land of Egypt, both the firstborn of man and the firstborn of animals. Therefore I sacrifice to the LORD all the males that first open the womb, but all the firstborn of my sons I redeem.’ It shall be as a mark on your hand or frontlets between your eyes, for by a strong hand the LORD brought us out of Egypt.”
ESV: English Standard Version 2016