Answer:
The Kingdom of God" is primarily a temporal designation. It's not so much about a people, a place, or a principle - It's a timeframe, an age, an epoch. In the Jewish hope, the coming of the Kingdom Age would mean the ending of the current one. The coming of the Kingdom Age would mean the fulfillment of all of the OT promises. But Jesus modified the OT scheme to teach instead that the New Age had come in him, and the promises were fulfilled in him. But, in a surprising twist that he referred to as "the mystery of the kingdom," the old age had not yet passed away. The New Age began, but the Old Age didn't end. Thus, the two ages overlap, instead of coming right after one another. And we currently live in the “overlap” between the ages. We have shared Craig Blomberg’s chart to illustrate this.