Yahweh has delivered Israel in mighty and impressive fashion. Now we come to Mt Sinai where God will give the Ten Commandments and the rest of the law to Moses for the people of Israel. This is an immensely important stop in Israel's ongoing journey. They will spend eleven months at Sinai. The biblical telling of this period begins here in chapter 19, continues through the rest of Exodus, the entirety of the book of Leviticus, and onto the tenth chapter of Numbers. For all the importance of the exodus and its centrality to Israel's story, it doesn't receive nearly the amount of attention that the law does in Israel's telling of its own story with God.
But really to separate the two that way is itself a mistake. It could be tempting to see the time at Sinai as a dramatic break from the story of deliverance which has preceded it. Perhaps upon reaching Exodus 19 we imagine that the story of liberation has come to a close and has now given way to the time of law. Maybe Yahweh has delivered these slaves from Pharaoh's rule only to make them his own slaves? God has delivered them and now he has them right where he wants them; weak and vulnerable in the middle of nowhere without even the Egyptians to run back to. Is the God who seemed so benevolent now "cashing in" on all he has done for these people? Is this law how Israel will pay God back?
In the stories of the exodus, the Red Sea, the provisions of fresh water, manna, and quail, we've seen that although God has removed this people from their slavery there are still many ways in which their slavery has not been removed from them. Although they have been delivered, they still don't know any other way to live than as Pharaoh's slaves. That is exactly why the giving of the law is a necessary and essential part of this story of liberation. God's Law is not something separate from God's liberation; it is not an obligation to be repaid to the God who has saved Israel. The Law itself is a part of God's liberating work. It is the natural next step in God's liberating work because this is how God will break the invisible chains of Pharaoh's oppressive regime which still reside in the hearts and minds of his people. The Law is God's way of teaching Israel how to live without Pharaoh telling them who they are. It is not a new slavery but the very way God has provided for Israel to live into their freedom.
Neither is this law-giving a one and done kind of deal. These are not instructions meant to take the place of God whose work is now done. No, this law is a covenant, a sort of contract, a binding agreement. That is, the God who has delivered Israel so mightily, defeated Pharaoh so completely, and who now covers this mountain in cloud and smoke, this tremendously holy God has bound himself to these slaves and allowed them to be bound to him so long as they respect God's holiness. Their fate will be his fate, their reputation his reputation. Yahweh says in v.5 "Now therefore, if you will indeed obey my voice and keep my covenant, you shall be my treasured possession among all peoples, for all the earth is mine; and you shall be to me a kingdom of priests and a holy nation. These are the words that you shall speak to the people of Israel." These former slaves will now represent Yahweh to the rest of the world so they must be holy as he is holy.
In 1 Peter 2, the Church is described in this very same language. Peter says to the churches of Asia Minor "But you are a chosen race, a royal priesthood, a holy nation, a people for his own possession, that you may proclaim the excellencies of him who called you out of darkness into his marvelous light." Israel's story is our story. We too have been brought into covenant with this redeeming God by the blood of Jesus Christ. Peter began his letter by addressing these churches as
the "elect exiles of the dispersion.... according to the foreknowledge of God the Father, in the sanctification of the Spirit, for obedience to Jesus Christ and for sprinkling with his blood". Just as the people were sprinkled with the blood of an animal at Sinai in order to seal this covenant with Yahweh, likewise the blood of Jesus Christ has sealed us into this new covenant. In this new covenant, our law is given not on stone tablets but in the person of Jesus Christ. He is our model of what it means to be holy as God is holy and it is his Spirit which enables us to live into the freedom which God has provided for us.