The people of God were to make themselves ready for a journey. I imagine how silly it may have felt to be eating the meal that day, dressed for travel, with staff in hand. How difficult it would have been to believe that hundreds of years of slavery could be finally coming to an end. The mixed feelings present at the table about leaving Egypt, while a place full of burden and difficulty, it was the only home this generation and many before it had ever known. The meal preparations and consumption would be the first in a series of many tests of faith for the people of God.
God had already demonstrated in the previous nine plagues that God was at work on Israel’s behalf. The laser-like precision of the plagues demonstrated God’s care for Israel; only Egypt and their possessions had been devastated by the locusts, darkness, and boils. What is interesting about the tenth plague is now God asks Israel to act in order to be spared. God already knew where they lived, where the boundary was between Egypt and God’s own people. Why the need to paint the doorway with sacrificial blood?
For other cultures and religions of the ancient world, blood and the color red were often used to ward off evil spirits and demons. But this time, the blood signifies for Israel much more. For as we will see later in Scripture, blood in Israel’s rituals and practices is not merely a symbol or superstition; blood for the people of God purifies. The blood on the doorposts is applied with hyssop, another tool of purification and cleansing (Psalm 51:7). Painting the doorposts is more than another test of faith.
A second piece of the puzzle is in the Hebrew verb pesah. The verb is often translated as meaning “pass over” as in the plague of death would see the blood and the plague would go on to another house. But pesah can also mean protect and deliver (see Isaiah 31:5). In this sense, verse 13 would best be read as “when I see the blood, I will deliver you.” For those of us who know the end of the story, we know the deliverance God is providing is beyond rescue from the tenth plague. The sacrificial blood and hyssop not only deliver their firstborn children and animals, but these also deliver them and purify them for rescue from Egypt, and prepare them to step into their role as the firstborn of Yahweh.
In Exodus 4:22, God says, “Israel is my son, my firstborn.” The firstborn in the ancient world is the one who would inherit a family’s wealth and responsibilities, the title of firstborn denoting a special relationship between a parent and child. The people of God had a choice that night to become Yahweh’s firstborn, to be protected and purified by the blood of the lamb.
The blood around the doorway creates as an image of a birth canal as God “delivers” them through it. The people of God emerge from the safety of their homes, much like a womb, to be born anew as the firstborn of Yahweh. They leave comfort for the unknown as they step out and accept the Lord’s deliverance. Not knowing exactly where it will take them, but stepping into their identity as Yahweh’s firstborn.
The temptation will be to jump to Jesus as the Passover lamb, which is a comparison that can certainly be made. Jesus as the ultimate perfect sacrifice, without blemish, and it is His blood that saves us from eternal death. But this is an important moment in Scripture not only pointing to what is to come in the form of the Messiah. In this moment the people of God are transformed, willingly entering and accepting their status as the firstborn of Yahweh.
The people of God are commanded in Scripture to remember this night, to celebrate with a feast, not only as a reminder of their deliverance from Egypt, but of their status as the firstborn, the bearers of God’s image in the world and to the nations. They were saved that night, purified by the blood of the lamb, delivered by the grace of God through their faith in stepping over the threshold to follow.
The role of the firstborn is to represent a family to others, to instruct younger siblings, to carry on the family legacy. We too inherit this mantle as the firstborn of Yahweh, to represent the Lord and the Lord’s love to others, to instruct and disciple, to carry on the family tradition and make disciples in the nations.
 John H. Walton, Victor H. Matthews, and Mark W. Chavalas, The IVP Bible Background Commentary: Old Testament (Downers Grove: IVP Academic, 2000), 85.
 David Fohrman, The Exodus You Almost Passed Over (New York: Aleph Beta Press, 2016).