It is often noted that the epistles say very little about the Kingdom of God in juxtaposition with the gospels. This is one of the reasons why many are very confident that the historical Jesus spoke often about the kingdom. It seems to be something that his followers did not emphasize as much; therefore, it doesn’t make sense that they would have invented his Kingdom sayings. This has led to quite a bit of speculation as to why the church forsook a concept so important to Jesus himself.
I am beginning to think that “the gospel” may have come to include the proclamation of the Kingdom so that when the Apostle Paul writes, “I am not ashamed of the gospel…” (Rom 1.16) it was taken for granted that this included the proclamation that God has enthroned Christ as his King (see Rom. 1.3-4).
The first thing that made this come to mind is Mk. 1.14-15 which reads:
“Now after John had been taken into custody, Jesus came into Galilee, preaching the gospel of God, and saying, “The time is fulfilled, and the kingdom of God is at hand; repent and believe in the gospel.”
As one can see when Jesus comes to Galilee “preaching the gospel” (κηρύσσων τὸ εὐαγγέλιον) he discusses the soon coming Kingdom of God (ἡ βασιλεία τοῦ θεοῦ), which demands that one responds by “believing the gospel” (πιστεύετε ἐν τῷ εὐαγγελίῳ).
Could it be that many in the early church simply assumed that any talk of “the gospel” assumed “the kingdom”?