Notice I took special care to somewhat define the terms of the first argument but haven't attempted to define the second. That was purposeful. I did that because often I find that those who would argue for the increase of preaching the Kingdom often don't define what that Kingdom looks like beyond an accumulation of good works.
My thoughts here are going to summarize some of the ideas bouncing around in my skull regarding this tension but could (and may in the future) be expanded. I'm not rying to be exhaustive and I'm not turning this into a series. I just want to get some of this down in writing.
The best place I know to start is with Jesus and Nicodemus in John 3. Nick tells Jesus about how he has seen Jesus' works and knows he comes from God. He doesn't ask a question, he merely states what he has seen. Here is how Jesus responds to him:
3 Jesus answered him, "Truly, truly, I say to you, unless one is born again he cannot see the kingdom of God."
4 Nicodemus said to him, "How can a man be born when he is old? Can he enter a second time into his mother's womb and be born?"
5 Jesus answered, "Truly, truly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God.
So we see both sides of the tension here: the need to be born again and the kingdom of God. Like love and marriage, you can't have one without the other and one precedes the other. I think everyone gets that.
The question then arises, can we talk too much about the need to be born again and too little about the advancement of the kingdom? I think so, check out what the writer of Hebrews says:
6:1 Therefore let us leave the elementary doctrine of Christ and go on to maturity, not laying again a foundation of repentance from dead works and of faith toward God,
So there is a sense in which we can focus too much on elementary things. Even so, as I recall many of the parables where Jesus led off with"the kingdom is like" he pointed in some way to the need to be born again.
Here's the thing: we don't need to be born again in order to want to help people, escape hell, be free from the guilt of sin, be healthy, happy, prosperous and live forever on streets of gold. We don't need to be born again to buy someone a meal, give generously to our favorite charity, be a friend in a time of need, or tell people about Jesus. These are some of the ways people describe the kingdom of God and they are good descriptions but something huge is missing and that missing piece is what should drive all our good works. The missing piece is an enthralled heart that is consumed with love and passion with the Christ that was crucified.
We must be born again to treasure, cherish, prize, and supremely value Christ above all things. As we find our delight in Jesus we move on to maturity in Him and advance the kingdom by displaying Christ as worthy above all things. This is what it means to be born of the Spirit. To focus on the things above in heavenly places with Christ and embrace the promises that are ours in Him is what the Kingdom is all about.
I believe this is why Paul continually preached Christ and wrote letters to the churches that brought their focus back on to Christ. When Christ is our all consuming desire and the outpouring of our lips, hands and feet the kingdom of God advances. Without Christ, efforts to build the kingdom build something apart from him.
I don't think we can talk too much about the need to be born again. Jesus only mentioned it twice in all recorded scripture and that was within the one conversation I quoted and the kingdom of God was spoken of 110 by Jesus during his ministry but that doesn't go to show what was more important for us to preach. Like I said, every place I can think of in which Jesus preached the kingdom, he was implying the need to be born again to enter it.
We can preach the kingdom in a way that excludes Christ and is made up of good works. We cannot have born again believers who love and delight in Christ above all things that are not advancing God's kingdom.
Do you think we can focus too much on one side or the other? What do you think the effects would be if we were lopsided in our focus?