the kingdom of God is not a place but a dynamic.Specifically, it was an intimate and productive dynamic with the Father and his people in which God got to actually lead and provide for humanity in the way he intended. Looking at the verbs of the NT, it was a dynamic with God and others, which we entered, or failed to enter, received or failed to receive. It was a dynamic that Jesus perfectly modeled for us and invited us into as his apprentices. The government of God had come and was looking for a people to govern and provide for.
This was amazing to me. I'm still dealing with the implications. But my first question was where does the cross fit in? As I read, I became aware of a long-running debate of which I had been totally ignorant—was it Jesus' gospel (the kingdom) or Paul's gospel (forgiveness via death and resurrection) that was the gospel? How exactly does "The kingdom of God has come near" fit together with "Christ died for our sins according to the Scriptures, that He was buried, that He was raised on the third day according to the Scriptures?" Where does forgiveness of sins fit in with the kingdom of God, or vice versa? One of the benefits, though, of coming late to a debate is that you get to hear, immediately, some of the better ideas that often only come after others have done much work. Another common theme that kept popping up in my reading was the narrative flow of Scripture. God doesn't do everything all at once. There is a story at work here, with characters, large and small, along with plots, subplots and more than one twist and turn before the end. As this big picture started to sink in, I began to see Jesus, his kingdom, his cross and his resurrection within this Story, and everything started to make sense. First the central character and the basic context of the NT: one cannot talk about the Jewish "Messiah" or "Christ" without simultaneously talking about "the kingdom of God" he is "Christ-ened" to lead. The Christ is a king, the King, who was to come, "restoring the kingdom." Jesus tended to talk about the kingdom (implying he was the Christ), while Paul focused on the main character—Jesus is the Christ!—assuming that everyone knows that the "Christ" leads a kingdom, the kingdom, God's kingdom. I started to understand that the historic connection between Paul's "Christ" and Jesus' "kingdom" is strong enough to bring substantial congruity all on its own. Second, though, the (messianic) plot: this king will, among other things, rescue God's people from their enemies, rebuild God's temple, bring God's justice to bear on the whole world . . . but how? The way I have come to see it, the early church saw the cross and the resurrection as the guts of the "how." It's how God's choice of king saved humanity from the dominance and fate of evil. It's how he rebuilt the temple of God. It's how he fulfilled the calling of the Jewish nation in general and the vocation of the Messiah in particular. It's also "how" a holy God can invite ordinary, messed up humans into an intimate collaboration. It's how Jesus brought the government of God near to humans in the form of an invitation instead of a death sentence. The cross and resurrection is the big climax, the ultimate surprise plot twist, of how the kingdom of God came to earth with peace and goodwill instead of a sword, even while the enemies of God and humans were completely dismantled! It's also the heart of how people will follow this king and become his people in this world, living examples and agents of his ongoing (and growing) rule. It is also the sign to the whole world, just as the Exodus was through superpower Egypt, that Yahweh is more powerful than the ultimate weapon of the most powerful human government on earth. God turned the symbol of Roman power into the ultimate ad campaign, into another stepping stool: Jesus is Lord with a capital "L.", everyone else should govern themselves accordingly. Jesus and Paul were indeed telling the same story of God's kingdom coming to earth, telling the same "good news" but Jesus was himself the main character--the king--living through the unexpected and intense climactic battle, and Paul was telling his story--which he understood as the story of the kingdom of God coming to earth, rescuing peoplefrom the kingdom of darkness.
And what was "the gospel" of the Old Testament? "How blessed are the feet of those who bring good news, who say to Zion, your God reigns." There are many gods and powers in the world, neutral at best and hostile at worst. The people of God in the OT and NT come to Yahweh and his Christ, enter and receive his reign over and for us, in substantial part, if at all because they believed he alone can treat the great powers of the world as podiums to stand upon or whatever else. He is the ultimate and highest Power in the world. He reigns, not least of which over the things which are the most menacing to people. And we rejoice, and jump at the chance to enter his government, his society, his never-ending administration on the earth. Eventually, it will be the only administration/society at work on the earth. Next will be how AA relates to this "gospel."