Summary: God set up all of Israelite life, so it'd be a constant reminder not simply of God, but of God's power. Why?
Let's start today, by reminding ourselves of where we are in Exodus.
At this point, Yahweh has killed the firstborn of every Egyptian-- from human, up to cattle. Pharaoh has released God's people from their servitude. And Yahweh gave favor to the Israelites, so that they could ask for anything of value from the Egyptians, and it would be given to them.
At this point in Exodus, the Israelites are wealthy, and free. They are loved.
This, in the OT, is God's great act of salvation. The Exodus is to an Israelite, what the cross is to us.
The thing that's maybe surprised us so far, is how much work God puts into making sure his people don't forget the moment of their salvation.
So far, we've mostly seen this through the Passover. The Passover serves as a reminder of this day of God's salvation, in a few different ways.
When God's people eat flatbread for a week, it's a reminder that they were so rushed, they couldn't wait for the bread to rise.
When they eat the lamb, it's a reminder of the lamb they ate that night, and the blood that they put on the door frame of their house.
When they stay inside all night, it's a reminder of the night that Yahweh sent the Destroyer throughout the land of Egypt, and of when Yahweh "passed over" their houses.
When they start every new year, they do so in remembrance of all of this. The calendar year is supposed to start, with a remembrance of God, and his salvation.
God is determined that his people not forget.
Our passage today adds to this.
Let's start in Exodus 12:51. It's maybe weird that we are taking one verse from chapter 12, but do you see the "and then" it starts with? This is a signal to us that we are starting a new story (see Biblical Hebrew Reference Grammar). And starting with verse 51 changes how we hear the passage as a whole. It helps us remember that what God is about to command his people, is connected to the exodus.
(and Exodus 13:17 has another "and then," so I'm self-consciously working with the units Exodus gives us, and saving that for next week. The easiest way to see this in English Bibles, if you don't read Hebrew, is to use the KJV, "and it came to pass,". It marks boundaries, and starts new stories.).
(12:51) and then, on this very same day, Yahweh brought out the sons of Israel from Egypt according to their armies/divisions,
(13:1) and Yahweh spoke to Moses, saying,
(2) "Dedicate/consecrate every firstborn-- the first offspring of every womb among the sons of Israel-- among human, and among livestock.
To/For me, it [is],
(3) and Moses said to the people,
"Remember this day that you came out from Egypt-- from the house of servitude--
because by a strong hand Yahweh brought you out from here,
and no one shall eat leavened bread.
(4) Today, you [are] going out in the month of Aviv,
(5) and then, when Yahweh brings you to the land of the Canaanites and the Hittites and the Amorites and the Hivites and the Jebusites which he swore to your fathers to give to you-- a land flowing with milk and honey-- you shall serve this service in this month.
Let's pause here. There's at least three things we should see here.
The first is in Exodus 12:51. Here, we have another reminder that Israel has become Yahweh's army. They are leaving "in their divisions." We will see next week that they don't necessarily understand this yet. God's people often don't see themselves, the way that God sees them. But what they (we!) have become, is God's army.
Second, the idea of "service" is key to these verses. When "you" were in Egypt, you served Pharaoh. He was harsh. You cried out to God, and He rescued you from that servitude. When you serve the service of the Passover, you remember your service to Pharaoh. And this service, of the Passover, is something that gives you joy. It's a festival. It's a feast. It's a reminder of how good God is, and it's a way to thank him, and acknowledge him.
What it's not, is legalism.
There is a yoke that's involved in serving God. God expects service. But his yoke is light, and easy. He is a far better Ruler than Pharaoh, or Satan, or Sin (Romans 6). Obeying God, is a delightful thing. It's done, out of gratitude, and it's done, out of a relationship with God. When the Israelites are serving the service of the Passover, they aren't obeying the book of Exodus. They are obeying God.
The third thing I want to focus on, is the new idea today. And that has to do with the dedication of firstborns.