Freedom isn't free, and the price for freedom is almost always blood.
The Exodus event is about freedom: freedom from the slavery of Egypt but also freedom from the slavery of sin. I do not think we can overestimate the importance of the Exodus, that is, the "exit" of Israel from Egypt. The Exodus event was THE event of the Old Testament. God never wanted his people to forget that he freed them, so he insisted that they remember this event every year. Passover is the yearly holiday celebrated in remembrance of the Exodus. We might think about the Passover as all of our American holidays wrapped into one – that is how important the Exodus was to both ancient Israelite identity and Jewish identity today.
Think about it. The Exodus is the official beginning of the nation of Israel (Independence Day). It celebrates emancipation from slavery (Juneteenth). It revolves around a special family meal (Thanksgiving), and it is most certainly religious (Easter and Christmas). The Passover remembers the most important event of Israelite history, but why exactly is it so important?
Freedom, that's why. Yet freedom isn't free, and the price for freedom is blood.
Israel's freedom cost blood, firstborn blood. Do you remember the Ten Plagues? God tried to convince the Pharaoh to let his people go. To show Pharaoh how serious he was, God performed miraculous signs through Moses, like turning water into blood and sending frogs into all of Egypt. But Pharaoh liked his slaves and refused to let Israel leave after each miraculous plague. Only the tenth and final plague convinced Pharaoh, at least momentarily, to let Israel leave. And the angel of God brought death upon every firstborn of Egypt, both animal and human, including Pharaoh's son. Only then, as he mourned his eldest boy, did Pharaoh relent.
The Israelite homes were different. Death did not visit these homes. These were the homes of God's people. The Israelites marked themselves as belonging to God with blood. This time it was the blood of year-old male lambs without any blemish or defect. All this symbolized the blood of the Lamb of God, the Messiah, whose blood would spare the new Israel (all believers) from the wrath of God.
So God commanded a yearly Passover meal of Lamb and unleavened bread as a commemoration of the Exodus event. But God also insisted upon another remembrance, more subtle than blood-stained thresholds. God commanded the Israelites to consecrate to him, or set apart as his, their firstborn males. It was almost as if God was saying, "You owe me! You owe me firstborn blood for your freedom." This is how Moses explained this new custom to the people of Israel,
In days to come, when your son asks you, "What does this mean?" say to him, "With a mighty hand the Lord brought us out of Egypt, out of the land of slavery. When Pharaoh stubbornly refused to let us go, the Lord killed the firstborn of both people and animals in Egypt. This is why I sacrifice to the Lord the first male offspring of every womb and redeem each of my firstborn sons." And it will be like a sign on your hand and a symbol on your forehead that the Lord brought us out of Egypt with his mighty hand (Ex. 13:14-16).
And yet God did not desire more human blood to be shed. So the firstborn boys of Jewish families were redeemed, that is, bought back, with another sacrifice: a lamb for wealthy families and two birds for the poor.
Faithful Jewish families would travel to the tabernacle and later to the temple to present their firstborn male to God. This included a young couple named Mary and Joseph. Forty days after giving birth, Mary, along with her husband Joseph, presented their firstborn Son at the temple and "bought" him back with a sacrifice of two small birds. This is known as the "Presentation of Our Lord" and is celebrated in the church on February 2.
All this reminded the Israelites of what God had done for them in the past, what it cost, and how precious this gift of freedom is. But none of it compared to the real slavery in which we are trapped (sin), the ultimate freedom earned for us (heaven), and the precious blood it cost (the Lamb of God). No amount of animal blood or ritual would do the trick. It would take the firstborn of God. Think of the irony of Jesus being presented at the temple. This is ultimately a symbol of the cross. He would be the firstborn offered as a sacrifice to pay for our freedom and to redeem us (buy us back).
Because of Jesus, there is no need for our sacrifice to God. There is no need to present ourselves before God. There is no need to redeem ourselves with a gift to God. There is no need to dedicate ourselves to God or to set apart anything for God. Christ does this in our place. Our "dedication" to him is only a natural result of salvation. This freedom earned for us wasn't free. Freedom never is. The cost is blood. Our blood isn't good enough, nor is anything else we offer. Only his blood will do. So he is presented at the cross, the firstborn of God.