Excellence, again, from Kevin DeYoung:
When you look at the Gospels and examine the verbs associated with the kingdom, you discover something surprising. Much of our language about the kingdom is a bit off. We often speak of “building the kingdom,” “ushering in the kingdom,” “establishing the kingdom,” or “helping the kingdom grow.” But is this really the way the New Testament talks about the kingdom? George Eldon Ladd, the man who put kingdom back on the map for evangelicals, didn’t think so.
The Kingdom can draw near to men (Matt. 3:2; 4:17; Mark 1:15; etc.); it can come (Matt. 6:10; Luke 17:20; etc.), arrive (Matt. 12:28), appear (Luke 19:11), be active (Matt. 11:12). God can give the Kingdom to men (Matt. 21:43; Luke 12:32), but men do not give the Kingdom to one another.
Further, God can take the Kingdom away from men (Matt. 21:43), but men do not take it away from one another, although they can prevent others from entering it. Men can enter the Kingdom (Matt. 5:20; 7:21;Mark 9:47; 10:23; etc.), but they are never said to erect it or to build it. Men can receive the Kingdom (Mark 10:15; Luke 18:17), inherit it (Matt. 25:34), and possess it (Matt. 5:4), but they are never said to establish it. Men can reject the Kingdom, i.e., refuse to receive it (Luke 10:11) or enter it (Matt. 23:13), but they cannot destroy it.
They can look for it (Luke 23:51), pray for its coming (Matt. 6:10), and seek it (Matt. 6:33; Luke 12:31), but they cannot bring it. Men may be in the Kingdom (Matt. 5:19; 8:11; Luke 13:29; etc.), but we are not told that the Kingdom grows. Men can do things for the sake of the Kingdom (Matt. 19:12; Luke 18:29), but they are not said to act upon the Kingdom itself. Men can preach the Kingdom (Matt. 10:7; Luke 10:9), but only God can give it to men (Luke 12:32). (The Presence of the Future, 193)
I’ve quoted this section several times, probably on this blog before. But when I’ve used it in the past I’ve been uncomfortable with the line “we are not told that the kingdom grows.” It seemed to me that the parable of the sleepy farmer (Mark 4:26-29) and the parable of the mustard seed (Mark 4:30-32) clearly teaches that the kingdom grows. But as I’ve studied the passages more carefully I think you can make a good case that Jesus is not teaching about the growth of the kingdom as much as he is demonstrating that the kingdom of small beginnings will, at the close of the age, be the kingdom of cosmic significance. The kingdom may look unimpressive now, with nothing but a twelve-man band of fumbling disciples, but one day all will see its glorious end.
To borrow a tired cliché, the kingdom is what it is. It does not expand. It does not increase. It does not grow. But the kingdom can break in more and more. Think of it like the sun. When the clouds part on a cloudy day we don’t say, “the sun has grown.” We say, “the sun has broken through.” Our view of the sun has changed or obstacles to the sun have been removed, but we have no changed the sun. The sun does not depend on us. We do not bring the sun or act upon it. The sun can appear. Its warmth can be felt or stifled. But the sun does not grow (science guys, don’t get all technical, you know what I mean). This seems a good analogy for the kingdom.
God certainly uses means and employs us in his work. But we are not makers or bringers of the kingdom. The kingdom can be received by more and more people but this does entail growth of the kingdom. We herald the kingdom and live according to its rules. But we do not build it or cause it to grow because it already is and already has come. As Ladd put it, “The Kingdom is the outworking of the divine will; it is the act of God himself. It is related to human beings and can work in and through them; but it never becomes subject to them…The ground of the demand that they receive the Kingdom rests in the fact that in Jesus the Kingdom has come into history” (A Theology of the New Testament, 102).