The kingdom of God is all about action. The gospel of Mark outlines this well.
* John the Baptist preaches repentance, that people should come to the river to be baptised. Action is required in response.
* Jesus comes to the river to be baptised, even when he does not need to be forgiven of sins. (But the state of sin free living is still required.) Jesus models action, he shows more than tells.
* Jesus calls people to get the kingdom started with him, to confess their sins and believe. But how were they to believe? Was it just a thought in the heart? Action was required. Belief came about by following Jesus. Simon, Andrew, James and John all decided to act in response and went with Jesus.
* Jesus cast out a demon from a man in the synagogue. The way had been prepared by repentance of sins and baptism in the Jordan, but Jesus then began to clean house. Jesus went through out the towns and villages of Galilee to all the synagogues casting out demons. This action of Jesus was the beginning of implementation of his Kingdom. Jesus also healed Simon's mother in law and the many people that came to Simon's house and later to Jesus' house in Capernaum. This action was also a demonstration of his kingdom.
I think there are some very telling stories about repentance in the gospels. One of my favourites is the story of the woman caught in adultery. As there is no one to stone her Jesus tells her to "go and sin no more". This is the action that is required from her to repent. Repentance is not actually the presence of a contrite heart. It is in the act of going away and not sinning that repentance is actually lived out. Baptism is also part of the physical action required to couple with repentance. Words are not enough. This is one of the reasons that formulaic prayers for becoming a Christian can be so hollow and mean so little. It is not the prayer that makes someone a Christian, it is the going away and not sinning and then the following of Jesus by affirmative action.
It is my opinion that little of the Kingdom of God exists in the landscape of the western institutional church. There is a formulaic teaching going around that people need to repent of their sins once, (because Jesus died for sins once and for all, there is a misconception that repentance is once and for all also) and that after this no real action is required. Christianity becomes a religion of words and good feelings, but no copying of Jesus' behaviour, the modelling that he gave to us.
It is impossible to build his temple (the one temple of all believers) in a place where the kingdom does not already exist. I know of very few places in my own experience where- continual confession of sins occurs, demons are cast out, the sick are healed, the poor fed, the lonely invited in. Most of the expression I have seen of Christianity is a hollow expression of ceremonies with little action followed up (these are not meant to be sweeping generalisations against the people I know who do these things, but they are usually no more than 5-10% of any congregation, sometimes less).
Building the church before building the kingdom is putting the cart before the horse. I do feel a little stuck as to doing this in my own life. But I also know that it is only when the kingdom is built that Jesus' true ekklesia will come to life.