These few verses serve as one of the reasons why the Pentateuch lays at the foundation of our understanding of Scripture as a whole. Does one need a deep, rich understanding of it to come to Christ? No. Does a Christian, hungering and thirsting for righteousness, need an understanding of it to have the understanding of the whole of the Bible he desires? Yes.
Romans, Galatians, and Hebrews all deal specifically with one’s approach to the Law after the coming of Christ. They presuppose that one has at least some familiarity with it and what it says. They assume one sees these narratives and teachings as authoritative in some way.
As Exodus moves into chapter 19, a shift occurs. Previous to this point, the Bible has been narrative, telling one uninterrupted story. Sometimes it fast-forwarded, skipping ahead (from Genesis to Exodus, this occurred for example). With the arrival at Sinai, the text introduces a new genre within the narrative—law. The text becomes prescriptive, meaning it gives specific commands. God gives the Law within a narrative context, but for the next while, mainly what one receives in reading Scripture consists of what God commanded the people of Israel in the establishment of them as a nation under him.
That being said, we have not yet reached the Law proper just yet. What Exodus 19 says reminds the reader (as Moses’s repetition of the words of God reminded the people) of the coming covenant’s basis: God’s initiative (v. 4). Due to his saving actions, delivering them from the bonds of slavery in Egypt. This historical event provides a picture of what salvation looks like—deliverance from bondage. Being borne away from captivity on the wings of an eagle (see also Isaiah 40:31).
Sin enslaves; it holds people in bondage. They cannot help but follow its whims and wanton desires. The corruptions it produces are congruent with the horrors of slavery in Egypt. As we see sin wreak havoc on human lives and bodies and grieve, we understand we would be grieved and horrified to see a Hebrew slave beaten mercilessly by a taskmaster. This is sin. This is how truly hellish it is.
Exodus 19:5 sets the condition for the covenant from the side of God’s people: hear and obey God.
Does such a thing nullify God’s grace in this situation? May it never be! James would be quick to remind us that faith with no works is no faith at all. Paul, the greatest promoter of God’s grace in all of history stated that deeds should be done in keeping with repentance.
It would be terribly hard for the people of Israel to say that they had been freed from slavery in Egypt if they treasured their slavery in their hearts. We know they struggled with a desire to return at times. So it is with the Christian believer. Sin remains somewhat attractive to our simultaneously saintly and sinful minds and hearts. A difference remains, however, between struggling with sin and treasuring it.
By their obedience, they would serve as the people mediating the presence of God before the other nations. In their treasuring of their freedom from slavery and the God who saved them, they would communicate his righteousness to the nations around them. They would show the pagan nations the wonderful holiness of the Creator of all things (Exodus 19:6).
No covenant exists with God outside of his initiative to establish such a thing. He came to Israel by means of Moses the mediator. Moses went back and forth from God to the people, and God purposed those people to present him to the pagans around them. In the new covenant, the mediator is God himself. He is Jesus Christ. His people, they still serve as communicators of who he is, and what he has done. They remain the means of the speaking of his good news to those far from him. They do not beckon them to a temple, for the temple of the Holy Spirit is the Christian believer. Matthew 28:18-20 and Acts 1:8 command the people of the risen Christ to go forth and speak his name to pagan sinners. May we respond as the people of Israel in Exodus 19:8—what the Lord has spoken, we will do!