When we look at the Bible we see that the gospel is much bigger than saving souls for heaven. In his letter to the Ephesians Paul says that God's will is 'to bring unity to all things in heaven and on earth under Christ' (Ephesians 1:10). The problem with the gospel statement, 'Jesus died for our sins so we can go to heaven', isn't so much that it is wrong, but rather that it is too small. It is a reduction of the cosmic truth of what God is doing in and though Jesus Christ. And the big problem with this smaller gospel is that it can reinforce a division between heaven and earth that leads to an unhelpful dualism  in the lives of many Christians.
The more we think that God is wanting to take us out of this material creation and into a spiritualised heaven, the more likely we are to think that to be truly spiritual we must disengage from the everyday things of earthly life and focus on the inner life of the soul. This split in reality between heaven and earth, soul and body, the spiritual and the secular, has been a persistent thorn in the flesh of the church from the earliest times. It is present in the idea that we must treat our physical bodies harshly as a necessary spiritual discipline for the soul,  and in negative attitudes to sex as something best avoided if we want to live a pure spiritual life.
Even today this dualistic way of seeing reality provides an implicit background for many Christians, so that they see their lives divided into a primary spiritual realm of church activity, Bible reading, prayer and evangelism, and a secondary less important 'secular' realm filled by work, leisure, relationships and education. Cultural engagement, social action, creativity, academia and caring for nature, all become unimportant backdrops to the 'real' spiritual drama of saving souls for heaven. Yet as we have seen, God's plan is to bring everything in heaven and earth together under the loving lordship of Jesus Christ. What then is a better way to understand the relationship of heaven and earth?
the throne room of GodThe Bible writers focus less on the idea of heaven as a place 'out there in the universe where God lives' and more as the throne room of God.  This emphasises heaven as the place from where God rules and where his will is done. So rather than a location, I think it is better to see heaven as a dimension of reality — the dimension where God's will is done. The Bible story starts in Genesis with a meeting of dimensions, a perfect earthly garden where God's heavenly will is done. The mission God gives humanity is to extend his good and loving will so that the whole earth is brought under the dimension of heaven.  When the first humans rejected God and closed their hearts to his will, the way between heaven and earth was shut.  Yet God's response was not to sit in a distant heaven and wait for the faithful to find ways to reach him. His response was to open doors from heaven through which he could come down to earth and begin the work of redeeming a hurting and broken world.
There are many examples in the Bible of these doors from heaven to earth - Jacob's ladder,  the burning bush,  the giving of the law on Mount Sinai,  God coming to dwell on earth in the tabernacle  and the temple.  But in the gospel God opens a door in his very self by taking on human flesh; Jesus Christ is 'the heavenly man',  fully God and fully human, fully of heaven and fully of the earth. His mission, by dying and rising again, is to pay the price for the sins of humanity so that the holiness of heaven and the sin-infected earth can be reunited once again. Jesus didn't die just so that the souls of the righteous might escape to heaven. Jesus died so that everything in heaven and on earth might be brought together in one joyful and glorious new creation. That is what the apostle John saw in his final vision of a new heaven and a new earth. 
The extraordinary wonder of the gospel is that when you become a Christian you become a meeting place of heaven on earth. The Spirit of God comes from heaven to live within you so that you are empowered to carry out God's will on earth. You become a mini-tabernacle, a mini-temple, a mini-dwelling place of God on earth, from which the loving power of heaven can flow out to redeem the broken world around you. Telling people the good news of the gospel is vitally important because they need to know how they can become a part of heaven on earth. But the mission that God has given his Spirit-filled people is far larger than just winning souls for heaven: it is nothing less than being a part of bringing all things, in heaven and on earth, under Christ.
Christ is Lord over all
This is why there is no secular-spiritual split in the Christian life. As the Dutch theologian and Prime Minister Abraham Kuyper put it, 'There is not a square inch in the whole domain of our human existence over which Christ does not cry, Mine!'  Everyone has their unique part to play in bringing the kingdom of heaven to their square inch of the earth, no matter how small or insignificant we may feel that part to be. Christ is Lord not just of religious things or of souls, he is Lord of bodies and minds, of ideas and emotions, of science and the natural world, of medicine and ecology, of business and economics, of the whole of human history and the whole of human civilisation.
James Paul is director of English L'Abri and a former palliative care doctor