We have this two-way traffic in the Bible in which you first have to start with the Old Testament which illumines the New Testament. So you start with the OT and then go to the NT. There, in light of the surprising way in which the OT was fulfilled in Jesus, the NT will, in turn, illumine the OT. In other words, they illumine each other. Another way of saying this is that the NT is in the OT concealed, and the OT is in the NT revealed. The NT reveals the full, true meaning of the OT. Every passage in the OT must be read in the light of the time of fulfillment launched by Christ and in the documents that came out of that time. Everything in our NT had its first mentioning in our OT. But it’s even more than that.

illumines illumines illumines
OT  NT; NT  OT; OT NT and so on

In other words, you cannot fully understand the core events of Jesus in the NT (the Story) in its fullness unless you first know and understand the OT (the ‘story’ behind the Story). As such, the OT illumines the NT. But the NT also illumines the OT. So to understand the Story (in the time of fulfillment) you must first understand the story behind the Story (in the time of promise). However, you need the NT revelation of Christ to fully reveal what was really going on in the OT all along. Further, you cannot understand who Jesus is in his fullness unless you understand the various promises of the OT that address those specific matters that point to him such as the promise of the Davidic covenant, the promise of the ultimate Davidic king, the promise of the servant figure, the promise of the coming of YHWH to Zion and so on. The Story (the NT) only makes sense if we know the ‘story’ behind the Story (the OT). If we don’t know the story behind the Story, the NT Story is not nearly as rich and full. (And, without an understanding of the OT, sometimes the NT won’t even make much sense.) Thus, in light of this surprising fulfillment of our Hebrew scriptures (the OT) in Jesus, one must engage in what the Bible itself demands. The Bible itself demands a salvation-historical reading of the OT as fulfilled in Christ. So what does that mean?

For instance, in a salvation-historical understanding of the Bible, the Bible is like a play in which things that were appropriate for Act I of God’s divine drama may or may not be appropriate for Act V. In other words, things change as God progressively reveals to humanity what will be. Therefore, central to the Bible is this continually unfolding drama of salvation history which will ultimately be fulfilled in Jesus of Nazareth. It has to happen this way because as we progress through Scripture, Jesus will be found out to be both the Messiah and the Son of God. That is, Jesus will be found out to be the fulfillment of both streams of OT expectation, that of the (human) ultimate Davidic king expectation and that of the (divine) coming of YHWH to Zion expectation.

Because of this “further development” within God’s divine drama, as God progressively reveals matters to us in Scripture, we will see that there were certain things that were permitted in the OT which are no longer permitted beginning with NT times and beyond. That is, there is a salvation history being expressed as we move from God’s people Israel to the fulfillment of the process in Christ. So it’s like a play. For instance, violence and divorce that were permitted in the time of promise will not be permitted in the time of fulfillment. As such, once the kingdom is inaugurated, it will be a new situation at work. And, therefore, what was appropriate in the time of promise may not be appropriate in the time of fulfillment. Thus, the Bible must be read through a salvation-historical reading of the text in which it all gets fulfilled in Christ. And because of this, certain things that were appropriate in Act I or II may no longer be appropriate at a later stage in the play. {See notes Lk 9 56.} When properly read, one will see that the whole of the OT always looked forward to Jesus’ activity in his praxis and his teaching that we see in the NT.

But it works the other way as well. Knowing the NT allows you to read the OT in a whole new way. Unless you understand the surprising fulfillment of the NT, you won’t understand what was latent all along in the OT. In other words, when you see the fulfillment (in Jesus in the NT), that, in turn, illumines the promise of the OT. That which was mysterious and dark within the OT is then revealed in the NT. The NT reveals the full, true meaning of the OT in a way you could not have known it apart from the fulfillment which is revealed in the NT. So it’s a two-way traffic with each testament illumining the other. Hence, two-way traffic provides a luster to the individual texts that they would not otherwise have.
For example, in the NT we have the two-stage kingdom of God, something which was never evident in the OT. Then, when the kingdom of God comes in the NT, we see that there are these two stages of inaugurated eschatology involved. The inaugurated kingdom of God will come with Christ’s first coming, and that will be later followed by the consummated kingdom of God which will come with Christ’s second coming.

Now, we are not to get the impression that the NT is saying that the OT was wrong and that the NT is correct. Nor is it saying the OT needs to be corrected by the NT. Instead, the understanding is that the OT was mysterious and the NT unveils the mystery. For instance, in reading our OT we would never know that the kingdom of God would come in two stages. Nothing in the OT even hints at that. However, as we learn once we get to the Incarnation in the time of fulfillment in the NT, a two stage kingdom of God was always God’s plan. In the Incarnation the human and divine kingships were united in one person – the hypostatic union. That is just another one of the many examples we have in Scripture of what the theologians call progressive revelation at work.

The gospel writers make this point over and over. They will not only say “here’s the story behind the Story”, but they also say “now here’s the fulfillment of that story”. They will say that in light of the surprising fulfillment of the story in Jesus’ death and resurrection, we must now read the story behind the Story in a whole new way. In other words, we must read our OT story through the lenses of Jesus’ death and resurrection. Now that the fulfillment has come in Jesus, we can now look back and see that the Hebrew scriptures were all about this Jesus of Nazareth person to begin with. Once we read our Scriptures through the lenses of the resurrection, we can see more clearly how it was all meant to fit together. The fulfillment has illumined things for us in the story (the OT story) that are now much more clear and understandable than they would have otherwise been before the fulfillment (the NT Story) had come.’ The story behind the Story.

In light of the surprising fulfillment of the NT, the OT story must now be read in a whole new way – and that way is ‘in the light of Christ’. As such, the NT reveals the full, true meaning of the OT in a way you could not know apart from the fulfillment in Jesus. This is why we have this very Christ-centered exegesis of the NT that we’ll see, for example, all through Paul’s letters. And, as another example, we have these animal sacrifices provided for by God through Moses, animal sacrifices that were meant for the forgiveness of sins. And yet, as the author of He put it, the blood of bulls and goats could never take away sin (He 10 4). So what was going on there?

As another example regarding the two-way traffic between the Old and New Testaments, Mark, for example, would say that you need the OT to understand what he’s saying in his gospel. Mark himself was also acknowledging that there is this two-way traffic between Old and New Testaments. Mark would say that you need the NT to fully illumine what was actually hidden there in the OT. The two-way traffic of the Bible. And as yet another example, we would have never experienced the thrill of the surprise of how Jesus most unexpectedly and shockingly fulfilled both streams of expectation found in the OT unless we first knew about those two streams of expectation from our study of the OT and that they were two very distinct streams. Then, once we see that’s how the fulfillment actually came, we can then go back to the OT and, as the NT authors tell us, we can see that that was God’s plan all along. We can then see that God’s plan of salvation was always going to involve this one God-Man, Jesus of Nazareth, who would fulfill both streams of expectation. And we learn all these things by better understanding this two-way traffic of the Bible.

Another example is that of the ‘son of God’ / ‘Son of God’ figure found in both testaments. When you see the Messiah referred to as ‘son of God’ in passages like Ps 2, when you see the messianic titles in Is 9 – to us a son is given, a child is born and his name shall be called wonderful, counselor, mighty God, the Jewish people understood those phrases in a messianic sense – a functional sense. These texts didn’t mean that this figure would be divine. Instead, it did mean that they were talking about the (human) Messiah. However, in light of the fulfillment seen in our NT, the phrase ‘Son of God’ now has now attained its fullest sense. That is, we see that the ultimate Davidic king actually was the divine Son of God. He really was God. So we’ll see that latent in the OT prophetic words of Isaiah and the psalmist was that the phrase ‘son of God’ all along had this divine sense also because Jesus was the Son of God not only in just a functional sense but in the ontological sense as well. Jesus truly was / is the Son of God. He is God! He is divine!

And then there was the tension we saw with having a human ultimate Davidic king. Every reader of the OT sees this tension because numerous OT texts repeatedly tell us that only God is to be the king of Israel and of all the earth. There was to be no king but God. This explains why when the people of God first come into the land, they are ruled by judges (See Jd 8 22-23 notes.). Still, God gave them a king, Saul, and then later God gave them an everlasting Davidic throne and later still even an ultimate Davidic king on the throne as a central part of his plan. That created not only an intellectual problem, but it was also an actual problem throughout the Davidic monarchy because most of the time the kings were always leading the people astray from God to other gods. An understanding of two-way traffic helps us resolve that tension and mystery because in the fulfillment we see that the human Davidic king was and is, in fact, YHWH come in the flesh as our King. This tension surrounding the ultimate Davidic king was thereby dissolved in the fulfillment. The whole problem of why God did it the way he did is resolved when we see the fulfillment. Hence, the biblical writers will tell us that the human Davidic king is God your king. Therefore, they would say, that was what God had in mind all along – that this was the fulfillment that would come and thereby resolve the whole tension and problem.

And we know all of these things when we employ our newfound understanding of ‘two-way traffic’!!!