As I’ve said before, in print and on this blog, I don’t think the talk of “building the kingdom” or our role in “ushering in the kingdom” is language that can be supported by Scripture. God already reigns, and he doesn’t need our help to get on the throne!). The kingdom of this world will become the kingdom of our Lord and of his Christ. We should live out the ethics of the kingdom, pray for the kingdom, and by faith we can receive the kingdom. But we do not bring about God’s reign.
Along these lines, here’s John Goldingay in his soon to be released Old Testament Theology: Israel’s Life:
The Psalter goes on to protest about how things are in the world (Ps. 3; 4; 5). Here a link between politics and ethics on one hand and prayer on the other becomes more overt. The world’s not being as it should be may be a reason for human initiative; it is certainly a reason for prayer. Ethical commitment without calling on God appropriates too much responsibility to us as human beings.
The Psalms will later declare that “Yhwh reigns” or “Yhwh is king” or “Yhwh has become king” (e.g., Ps. 96:10). Generally speaking, it does not look as if this is the case. Israel’s world often looked like one in which Pharaoh or Sennacherib reigned, not Yhwh, as our world does not look like one in which Jesus is Lord. Like us, then, when Israel entered worship and declared that Yhwh reigned, it was often making statements that went against the evidence. It was creating a world.
Admittedly, talk of “creating a world” could be misleading. The Psalms’ conviction is that in the real world (as opposed to the world that we see) Yhwh indeed reigns. In worship we are making the already-real reality in our ears and before our eyes. We may then be inspired to go and live out our ethical and political commitment in the world outside worship in the knowledge that the world in which Yhwh reigns is indeed the real world. But we would be unwise to make that a covert way of reckoning that it is our task to bring about Yhwh’s reign, which would be laughable if it were not a Christian heresy that is alive and well (p. 27 [paragraph breaks are mine]).
We would do well to expect less of the “already” in the world, and expect to see more of it in our worship. I encourage you to read the Goldingay excerpt a second time.