The outline of Israel’s life at this time is unique. They have left Egypt, been brought out as God’s possession. We are all by now accustomed to the idea that Israel was not saved for their own sake, but for the sake of the LORD. They themselves are not free from having some sort of yoke, but YHWH is now their master instead of Pharaoh. And it is a yoke of worship, devotion and, as they will discover, some kind of moral purity reflective of the purity of YHWH.
But we aren’t there yet. Exodus 19 is about the preparation for the Decalogue that comes in chapter 20. While we have the benefit of hindsight, that they will inevitably be made into a people with a common history and culture and belief and covenant, that could not have been clear at the moment. Just like the disciples of Jesus gathered in that room before Pentecost, something marvelous has happened, but what is it going to mean? Who are they going to be?
They are 50 days on since the Passover. They gather at the mountain. The cloud descends. Moses goes up. All of this, for us Christians, has a ring of Transfiguration and Pentecost. Having traveled from Egypt and through the Red Sea, there is a gathering and a pause before the mountain. Looking backward, the Lord reiterates to Moses that he did what he promised he would (v. 4). He then looks forward to being a treasured possession among the peoples and therefore a holy and priestly people (v. 5-6).
Moses relates this to the people who receive it with a commitment to obey the Lord and keep his covenant. Interestingly, they don’t yet know what the covenant is. But it doesn’t matter! And that is the thing about this life lived under God’s word. We simply come under the Word and allow God to then do his work. The idea that we are going to know what that contains, that we are fully cognizant of what we are agreeing to–it can’t be done. In our powerlessness, we are reconciled to God by no action of our own (Rom. 5:6ff). That is grace. And so the proper response is then utter devotion to the Lord, come what may. It is finding yourself in the midst of his covenant saying that you will obey and not knowing what that will entail, but trusting that God will give you the grace to accomplish it because this is the God who frees slaves and raises dead Messiahs.
With an eye to the Matthew passage this week, we might rightly emphasize the vocation of the people of God. The disciples go out as missionaries of Jesus’ kingdom-message. Israel is constituted to serve YHWH as his priests. Just as Moses is for Israel, going up and down the mountain, so Israel is to be for the world, constantly ascending and descending Mount Zion, making the sacrifices, praying the prayers on the world’s behalf, lifting them up before the Lord. This is the pattern. The priests go back and forth between the high and dry world of theophany–there is a lot to be desired about the mountaintop, but it is not a great place to live–and the everyday place of pasture and wilderness where we find ourselves spending most of our actual days.
But we don’t get into this knowing what it will entail. We may have to eat unleavened bread. We may have to travel without any extra money, bags, or clothes. We, commissioned representatives, are to live a somewhat sparse life because our salvation is not for our own good as we define it, but for the good of the world, which all belongs to God.
Harold Senkbeil in his excellent book The Care of Souls, calls pastors sheepdogs. Quoting Evelyn Underhill, he writes, “That dog was the docile and faithful agent of another mind. He used his whole intelligence and initiative, but always in obedience to his master’s directive will; and was ever prompt at self-effacement….The dog’s relation to the shepherd was the center of his life…”
And this is what Israel ought to have been: a kingdom of priests, self-effacingly doing the work of the Shepherd in worship, service, and witness. Once we have got clear just what has happened at our salvation and the harvest we are called to, we can get on to the 1 Peter business of “proclaim[ing] the excellencies of him who called you out of darkness into his marvelous light” (1 Pet. 2:9).
This is true of Israel in its relationship to all the other peoples of the ancient world. It is true of the pastor in her relationship to the church. It is true of all Christians in relationship to the broader world. But maybe Exodus is just the reminder we need that this vocation is not about us. It is about the LORD who has won our salvation from Pharaoh and assured our future within the confines of obedience to his covenant-love.
 Cole, R. A. Exodus: an Introduction and Commentary. Vol. 2. Downers Grove, IL: IVP Academic, 2008, 150-154.
 Lienhard, Joseph T., and Ronnie J. Rombs. Old Testament. Vol. 3. Downers Grove, IL: InterVarsity, 2001, 95-96.
Senkbeil, Harold, The Care of Souls (Bellingham, Wa: Lexham Press, 2019), 122-123.