Because the first born in all of Egypt died on the night of the Passover, all first males must be dedicated to the LORD. Moses explains that the feast of unleavened bread is to be keep each year during the first month. He stresses the importance of teaching these things to future generations so they never forget what God has done.
Exodus 13
The LORD spoke to Moses, saying,
2 “Sanctify to me all the firstborn, whatever opens the womb among the children of Israel, both of man and of beast: it is mine.”
3 Moses said to the people “Remember this day, in which you came out from Egypt, out of the house of bondage; for the strength of the LORD’s hand brought you out from this place: there shall no leavened bread be eaten.
4 This day you came out in the month Abib.
5 When the LORD brings you into the land of the Canaanites, Hittites, Amorites, Hivites and 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.
6 Seven days you are to eat unleavened bread, and on the seventh day there shall be a feast to the LORD.
7 Unleavened bread shall be eaten seven days; and there shall be no leavened bread seen with you, neither shall there be leaven seen with you in all your territory.
8 And you shall show your son in that day, saying ‘This is done because of what the LORD did for me when I came out of Egypt.’
9 It will be a sign for you on your hand, and for a memorial between your eyes, that the LORD’s law may be in your mouth: for with a strong hand has the LORD brought you out of Egypt.
10 You must therefore keep this ordinance in its season from year to year.
11 When the LORD bring you into the land of the Canaanites, as he sware to you and to your fathers, and gives it you,
12 That you are to set apart to the LORD all that opens the womb, and every firstling born of an animal which you have; the males shall be the LORD’s.
13 And every firstling of a donkey you shall redeem with a lamb; and if you will not redeem it, then you must break his neck: and all the firstborn of man among your children you shall redeem.
14 And when your son asks you in time to come ‘What is this?’ you will say to him ‘By a strong hand the LORD brought us out from Egypt, from the house of bondage.
15 When Pharaoh stubbornly refused to let us go, that the LORD killed all the firstborn in the land of Egypt, both the firstborn of man, and of beast: therefore I sacrifice to the LORD every male that opens the womb; but all the firstborn of my children I redeem.’
16 So let it be a sign on your hand, and a symbol between your eyes: for with a strong hand the LORD brought us out of Egypt.”
17 When Pharaoh had let the people go, God did not lead them by way of the land of the Philistines, although that was near; for God said “The people might change their minds when they see war, and return to Egypt.”
18 But God led the people around by way of the wilderness of the Red sea: and the children of Israel went out of the land of Egypt equipped for battle.
19 Moses took the bones of Joseph with him: for he had made the children of Israel swear an oath, saying “God will surely visit you; and you shall carry up my bones away from here with you.”
20 They journeyed from Succoth, and camped in Etham, at the edge of the wilderness.
21 And the LORD went before them by day in a pillar of a cloud, to lead the way; and by night in a pillar of fire, to give them light; to go by day and night:
22 He did not take away the pillar of the cloud by day, nor the pillar of fire by night, from before the people.
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