Don't want your law and order
Or world wide disorder
I don't imagine it's what The Runaways intended, but that isn't a bad summary of what Jesus meant by the Kingdom of God. If the Kingdom isn't about restoring lost souls, at least as much as saving the respectable, then it doesn't have much meaning at all.
It was Harvest Service at St John's last Sunday, for which this year's lectionary readings were ... interesting. Joel's prophecy of hope, where God promises to "repay you for the years the locusts have eaten". and Jesus' sermon on the mount, where he tells us to "seek first the Kingdom of God and his righteousness, and all these things shall be added to you," where 'all these things' are food and clothes and all the practical stuff.
The word translated 'righteousness' here also means 'justice'. And 'justice', for Jesus, was very definitely not the same thing as the Law. Following the law means being respectable: obeying the rules, where the rules have been carefully tweaked and tailored to favour the rich and powerful. Justice involves turning things upside-down: shaking things up so that those who have fallen to the bottom of the pile, in this fallen world, get their chance to find the top.
What sort of people can be expected to do best in a world of wrong? And who is likely to hit the bottom in such a world?
Jesus taught of an upside-down Kingdom where all that we thought we knew from living in this one is turned backwards. A world where the contributions of the poor are valued more than the crumbs of the rich, where importance depends on service and humility, and where peace can trigger division. In particular this is a Kingdom where justice, peace and reconciliation matter vastly more than wealth and status - the latter just get in the way.
One oddity of all Jesus' talking about 'The Kingdom' in the Gospels is that he never defines what he means by it. It looks as though everybody knew what the Kingdom of God/Heaven was, so Jesus was simply building on that common knowledge foundation. For many centuries that 'common knowledge' was lost so theology on the Kingdom has always been a bit like an upside-down pyramid - lots of ideas based on a very slim foundation. Thankfully over the past half-century or so a lot of documents have been recovered from the Eastern Mediterranean, dating to a little before Jesus' time, which gives us a better idea.
In essence those waiting for 'The Kingdom' were waiting for a true end to exile, for God to found a nation of true justice and peace. By and large the Jews expected this to be a Jewish kingdom, although some noted that parts of the Law and the Prophets referred to Gentiles being included as well. This Kingdom would be ruled either by God Himself, or by a king from David's line chosen by God, reigning as a good and faithful shepherd. By Jesus' time these expectations of a just kingdom were linked with expectations that the remaining unjust kingdoms, ie the rest of the world, would either come to an end or they would become subservient to God's Kingdom.
A lot of Jesus' teaching was about who would qualify to be citizens of this Kingdom - including many people who respectable Jews would not expect to see there - and about the Kingdom breaking through ahead of time, so to speak. Thus Jesus' healings and teaching are signs of the Kingdom, as are those who are lost but become found, and those who seem dead being restored to life.
At the end, the New Testament gathers these Kingdom ideas together in a vision of a new world, where God Himself comes down to live amongst his people, and where citizens of the Kingdom, even the seemingly unworthy, are raised back to life, if they have died, or been transformed to new life, if they are still living at Jesus' return.
I saw the Holy City, the new Jerusalem, coming down out of heaven from God, prepared as a bride beautifully dressed for her husband. And I heard a loud voice from the throne saying, “Look! God’s dwelling place is now among the people, and he will dwell with them. They will be his people, and God himself will be with them and be their God. ‘He will wipe every tear from their eyes. There will be no more death or mourning or crying or pain, for the old order of things has passed away.”