Then the Lord said to Moses, 2 “Dedicate to me every firstborn among the Israelites. The first offspring to be born, of both humans and animals, belongs to me.”
3 So Moses said to the people, “This is a day to remember forever—the day you left Egypt, the place of your slavery. Today the Lord has brought you out by the power of his mighty hand. (Remember, eat no food containing yeast.) 4 On this day in early spring, in the month of Abib,[a] you have been set free. 5 You must celebrate this event in this month each year after the Lord brings you into the land of the Canaanites, Hittites, Amorites, Hivites, and Jebusites. (He swore to your ancestors that he would give you this land—a land flowing with milk and honey.) 6 For seven days the bread you eat must be made without yeast. Then on the seventh day, celebrate a feast to the Lord. 7 Eat bread without yeast during those seven days. In fact, there must be no yeast bread or any yeast at all found within the borders of your land during this time.
8 “On the seventh day you must explain to your children, ‘I am celebrating what the Lord did for me when I left Egypt.’ 9 This annual festival will be a visible sign to you, like a mark branded on your hand or your forehead. Let it remind you always to recite this teaching of the Lord: ‘With a strong hand, the Lord rescued you from Egypt.’[b] 10 So observe the decree of this festival at the appointed time each year.
11 “This is what you must do when the Lord fulfills the promise he swore to you and to your ancestors. When he gives you the land where the Canaanites now live, 12 you must present all firstborn sons and firstborn male animals to the Lord, for they belong to him. 13 A firstborn donkey may be bought back from the Lord by presenting a lamb or young goat in its place. But if you do not buy it back, you must break its neck. However, you must buy back every firstborn son.
14 “And in the future, your children will ask you, ‘What does all this mean?’ Then you will tell them, ‘With the power of his mighty hand, the Lord brought us out of Egypt, the place of our slavery. 15 Pharaoh stubbornly refused to let us go, so the Lord killed all the firstborn males throughout the land of Egypt, both people and animals. That is why I now sacrifice all the firstborn males to the Lord—except that the firstborn sons are always bought back.’ 16 This ceremony will be like a mark branded on your hand or your forehead. It is a reminder that the power of the Lord’s mighty hand brought us out of Egypt.” Exodus 13: 1-16 NLT
The spiritual implications are strong here. A day to remember forever, and as Israel is now freed from it's physical captors, they are told of this time, not to eat that which contains yeast. There is a slavery that men do not recognize as such, and the picture should lead us to inquire of this state.
They answered Him, "We are Abraham's descendants and have never yet been enslaved to anyone; how is it that You say, 'You will become free '?" 34Jesus answered them, "Truly, truly, I say to you, everyone who commits sin is the slave of sin. 35"The slave does not remain in the house forever; the son does remain forever.…John 8:34
On the seventh day, it must be explained to the children. The story does not end here, and it is profitable to all generations. It is the message of sin, God's Sovereignty, and His provision of a Lamb. The first born of all men and animals were to be dedicated to God, and that in sin is death, all first born humans must be bought back by substitution. It is before the tabernacle or the Levitical priesthood. Those firstborn would be set apart to do God's work, and they would be, for a time, the priest unto their families. What do you tell the children? Do you tell the children? So many years later, as I reflect upon this story, I see the end of it, the Lamb of God that Israel could not then see. The story of Messiah and the need of a Savior was long ago established, before He ever took the cross. There, on that cross, He set me free, God's first born, the substitution, but on the third day He arose and so on Sunday, we now celebrate. It is a day to be remembered for all time, a day to tell the children. At the beginning of the week we explain the way and the reason for the rest of the week. Every day belongs to God.
I am speaking in human terms because of the weakness of your flesh. For just as you presented your members as slaves to impurity and to lawlessness, resulting in further lawlessness, so now present your members as slaves to righteousness, resulting in sanctification.20For when you were slaves of sin, you were free in regard to righteousness.21Therefore what benefit were you then deriving from the things of which you are now ashamed? For the outcome of those things is death.…Romans 6:19-21