In this video on the Kingdom of God and the Church, Dr. Brant Pitre discusses the relationship between Jesus' proclamation of the Kingdom and the coming of the visible Church. Are they the same reality, or are they different? Did Jesus promise the Kingdom and if so, did it come?
So in closing then I just would like to end with a reflection from St. Augustine in his Tractates on the Gospel of John. He has a number of tractates on John where he comments on this and he makes a point about the nature of Christ's kingdom. This is what he says: Indeed, his kingdom is here until the end of time, and until the harvest comes will contain weeds... And this could not happen if the kingdom were not here. But even so, it is not from here, for it is in exile in the world. Christ says to his kingdom, “You are not of the world, but I have chosen you out of the world” (John 15:19)... [E]veryone who is reborn in Christ becomes the kingdom that is no longer of the world. For God has snatched us from the powers of darkness and brought us into the kingdom of his beloved Son.2 So notice what Augustine does, he draws out one more implication of Jesus' words here, namely this, the relationship between the kingdom and the church. I'll never forget years ago I had a disagreement with a Protestant friend of mine about the kingdom, and it became quickly apparent that we saw it at completely different terms. For him the kingdom was something that would only come at the end of time; only at the final judgment would the kingdom come. For me, as a Catholic, the kingdom was already present in the church. When I tried to identify the kingdom in the church, he said no, no, no, the kingdom doesn’t have anything to do with the church, the kingdom comes at the end of time; the church is now, the kingdom is in the future. 2 Augustine, Tractates on the Gospel of John, 115.2; trans. in J. C. Elowsky, p.290 And it's interesting's because there is some truth to that. The kingdom will come in its fullness at the end of time, but the church is very clear here that the church on earth is the kingdom of God but present in mystery, right. It doesn't look quite like the kingdom but it is the kingdom, there’s still weeds and wheat in the field, so to speak. And you know this is the case because Jesus gives Peter the keys of the kingdom and makes him the foundation stone of his church, right. So in that statement to Peter in Matthew 16, kingdom and church are two ways of talking about the same reality. So I just think it's important to remember that. That although the church is essentially heavenly in her nature and she will only be fulfilled at the end of time, the church is the kingdom present in mystery, as Vatican II taught. So what Augustine is saying ßto us here is that insofar as we belong to the church, we live in this world, but we’re not of the world, because we belong to a kingdom that is essentially heavenly in character.
This is an excerpt from The Mass Readings Explained, which you can learn more about here.