When we think about the importance of the Old Testament to the Christian church today, there are a lot of views on this. Some would say that it is not important at all. Of course, in the Reformed world, we think it is very much important. Why is that? Why do we think the Old Testament has tremendous ongoing relevance to the Christian church today? Our understanding of salvation and all that it entails is entirely dependent on those kinds of concepts and vocabulary that show up in the Old Testament.

Imagine going to someone at a bus stop and you hit them with the gospel really fast and say, “You need to believe in Jesus who shed his blood for your sins so that you can be reconciled to God and go to heaven when you die.” All of that is true, but that person is going to look at you like an alien. They do not necessarily even have any understanding of those concepts to begin with. The gospel does not make sense without meaning to those words.

Our understanding of salvation and all that it entails is entirely dependent on… the Old Testament.

When we look at the New Testament, we can see how the authors always understand the work of Christ through the concepts, words, and ideas that are there in the Old Testament. Paul and John did not conjure up the implications of Jesus’ work such as ransom, reconciliation, justification, atonement, propitiation, and blood for sin out of nowhere. Those are Old Testament ideas. There was a basis for them in Israel Scriptures that they are then understanding in light of what Christ did.

You do not get salvation if you do not get the Old Testament. The Old Testament provides the whole structure of thought by which the New Testament expresses what Jesus really did. To support that idea, I would point to two particular passages where we see this very thing: Jesus himself on the Emmaus road as recorded in Luke 24.

What does he do when he is trying to explain the significance of what he has done? He says, “Everything written in the law of Moses and the prophets and the Psalms is about me.” Then, he clarifies it and he says, “As it is written.” The fascinating thing there is that he is not actually quoting anything; there is no actual quotation in the Old Testament. He is summarizing all of Scriptures teaching and he says that the Messiah will die for our sins, rise again on the third day, and repentance for the forgiveness of sins will be preached to all the nations. He says that is what the Old Testament teaches.

New Testament authors understand the work of Christ through concepts in the Old Testament.

He understands his own ministry in light of what he thinks the law of the prophets and the writings bore witness. Not only Jesus presents that idea, but also Paul. In the very important passage in 1 Corinthians 15, Paul says, “The gospel that I taught to you by which you were saved in which you stand is this: that the Messiah, the Christ, would die, that he would be buried, and that he would be raised again.” What does he do? He says, “He will die for our sins according to the Scriptures.”

For him, the core of the gospel, which is the proclamation of the same saving work of Christ, is rooted in fulfillment of the growth of the Scriptures that he is referring to. For Paul, for Jesus, and really for the entire New Testament, the building blocks of their understanding of the entire magnificence and glory of the work of Christ, points them back to what the Old Testament was anticipating all along.

To understand the significance of what Jesus has done, we have to go back to the Old Testament. Implicitly, that means the Old Testament has tremendous importance for us today.