Recently I received two e-mails within hours of each other. In the first, I learned of the tragic death of a young boy, whose parents – and many others, including me – had prayed faithfully for many months for healing from cancer... and who had died. In the second, I read the testimony of another young man, not yet a Christian, living on another continent, prayed for that week by his sister's Alpha group. This young man had just attended a hospital appointment at which confirmation of the original diagnosis of a similar tumour was expected... only to find he was completely in the clear!

Why was one miraculously healed and not the other? Why did the believers' child die, and the (as yet) unbelieving brother live? Why did a day or two's prayer from a few people yield amazing results, but not months of faithful intercession from many?

Nothing illustrates both the challenge, and the fundamental importance, of developing In-tension-al Faith more than those words 'now' and 'not yet'. It is, arguably, the central tension we live with as Christians: I have been saved, I am being saved, I will be saved. Which is it? Can it be all of them? Why do I already have 'every spiritual blessing in Christ' (Ephesians 1:3) and yet need to keep being filled with the Spirit (Ephesians 5:18)? How can I have died to sin (Romans 6:2) and yet find that 'sin living in me' (Romans 7:20) still keeps doing bad things? How much is 'now' and how much 'not yet'?

How near is 'near'?

This central tension is aptly illustrated by Jesus' own teaching on this subject. 'The time has come. The kingdom of God is' ....what? If you read The Message, you'll find it's 'here'. In the New King James it's 'at hand', and in the NIV or NRSV, you'll find it's 'near'. Here – or near?

Even more intriguingly, in the Lord's Prayer, Jesus refuses to indicate whether the kingdom has come or will come, he simply says 'Come your kingdom' (that's the literal translation of Matthew 6:10).

So it's no wonder that we struggle. I want to suggest that the 'Both/And' approach of In-tension-al Faith calls us fully to embrace both: the kingdom is now and the kingdom is not yet. And not just a bit now – properly now. And not just a bit yet to come, either.

Over-realised thingymajig

But embracing both has tended to be a challenge for the church – right from the very beginning. In Corinth, for example, the first Christians reckoned it was all 'now'. The extravagant outpouring of spiritual gifts which they had experienced led them to believe that heaven was their present reality. They spoke in the 'tongues of men and of angels', they possessed great knowledge (or so they thought), they lacked no spiritual gift. Everything was permissible now... including divisions, immorality, legal disputes, intellectual pride and demeaning of the Lord's Supper. The theologians call it 'over-realised eschatology', which is a fancy way of saying they thought they had it all already. As Belinda Carlisle might have sung if she'd lived in 1st-century Corinth, heaven was indeed a place on earth. Consequently, sin wasn't sin any more, they could do what they liked with their bodies because otherwise God wouldn't keep giving more of his Spirit to them, right?

Wrong. As Paul took 29 chapters across two letters to spell out – by far the longest of his recorded missives to any of the churches he communicated with – they hadn't grasped the fact that the kingdom was both now and not yet. The fervent spiritual atmosphere of their meetings couldn't disguise the fact that they lacked maturity: he even called them 'children', and not in a positive way. They might speak in tongues but in so many other areas they didn't walk the talk. God was graciously blessing them in spite of their behaviour, not because of it. They were still on the journey – nowhere near as far along, in fact, as they supposed.

Pie or steak?

On the other hand, many churches through the ages have tended to focus largely on the 'not yet'. This is entirely natural in contexts where tiny groups of Christians experience real persecution, but we also find it throughout the Western church, a byproduct either of Enlightenment rationalism (denying spiritual reality), resurgent Greek dualism (debasing the material world) or a theology that insists that we are so irredeemably corrupt that any real transformation is unlikely, we just have to cling on to God's grace until we die.

But what's missing here is that when Jesus called us to believe the good news, he also called us to repent, a word which often gets a bad press but basically means to change the way we live: not just at some unspecified point in eternity, but now. We often couch repentance in negative terms: but it is not just what we turn from but what we turn to. To holiness, yes, but also to fullness of life, to transformation, to an extraordinary adventure with Jesus.

Jesus lived and demonstrated the breaking in of the kingdom that he preached, but he did not reserve this privilege for himself. He sent his disciples out to do the same things (Matthew 10:8), and later promised that 'anyone who has faith in me will do what I have been doing' (John 14:12).

Steak first, pie later: what could be better than that?

Experiencing the now

So it is not just helpful to retain a strong sense of the 'now' of the kingdom. Discipleship requires it, in fact. As Dallas Willard helpfully summarised: 'Discipleship is learning how to live in heaven before you die.' God is not just keeping us alive until he decides to take us to heaven, he is equipping us to be ready for it. Heaven is not meant to be a terrible shock for us, like some celestial holiday resort which looks nothing like the photos, a place where we wake up and find ourselves saying: 'Ooh, I never thought it would be like this!' It will of course be utterly wonderful, better than we can possibly imagine, but the point is: its values are ones we should be trying to live now.

I have to confess I'm no fan of the carol Away in a manger. However, it does have at least one thing bang on the nail. Can you remember the last line? 'And fit us for heaven, to live with thee there.' How good a definition of the now of the kingdom is that? We are being 'fitted' for heaven. Why? Because when we finally get the awesome, unutterable privilege of living with Jesus eternally, we will in some sense already be 'fitted' for it, we'll have some idea of what that looks like.

It's not just about us, either. The rest of the world needs an idea of what heaven looks like as well. How on earth – literally – are they to do that? Most of the time, through us. To most of society, we are God's billboards for what life in heaven might look like. It makes intuitive sense: if you want to know what a country is like before you've been there, the best way is to meet its citizens. You can read guidebooks, visit websites, learn hundreds of words and phrases from a dictionary: but there's no substitute for personal contact. You can tell a culture by its people.

Christians are citizens of heaven. We have dual passports now, which is just as well for those of us with embarrassing real-life passport photos. And we have to admit that a theology which sees followers of Jesus essentially as grimly hanging on and waiting for death is profoundly unattractive to anyone who wants to experience hope as a present reality and not just a future payback. We need a bit of sizzle with our sausage, even if we retain a healthy realism about our human frailty and capacity to suffer this side of the grave.

Ultimately the 'now' of the kingdom is the outworking of what we pray every time we say the Lord's Prayer: 'Your kingdom come... on earth as in heaven.' That transformation is personal, social, even ecological. The 'now' of the kingdom affects every dimension.

Retaining the tension

But of course, there is the danger that those first Christians in Corinth fell into. If it's all 'now', how do we deal with unanswered prayer, sickness, suffering, and ultimately physical death? The answer is, surely, not to abandon the 'now' altogether. Poverty of expectation might allow us to cope with these challenges, but it is hardly the abundant life that Jesus promises. Rather, I would suggest three approaches which help us to honour the 'not yet' even as we strive passionately for the 'now'.

Through a glass darkly

I doubt St Paul ever experienced frosted glass on his bathroom window, but that's the sort of image he's getting at in 1 Corinthians 13. When we stare at heaven, we're looking through frosted glass. We get some idea of the contours, and the possibility of what the image might really look like is fantastically exciting – but, but... the fullness remains tantalisingly vague, just out of reach.

Imagine your greatest experience. And your most intimate relationship. Multiply it by 10. And extend it forever. That's what heaven will be like.

Put like that, believing that the limit of what we experience now is close to our future 'fullness' sounds (a) arrogant and (b) dangerous. God is way bigger than that.

Contented and discontented

...which is not a bad way to describe the spiritual life at any given point in time.

Contentment is a key by-product of the Christian life. As we experience the 'now' of God's kingdom, we see wonderful fruit like peace and joy flourishing within us, even in difficult circumstances. We strive for less, we envy less, we breathe more.

But that's not the whole story, is it? We also hope, which, Paul Wallis noted pithily, 'is a decision for discomfort and frustration'.Hope implies that things are not as they should be. Hope is an outworking of discontentment. But how we need it! Hope is also 'a decision to channel what makes you truly alive.'

In specific terms, Bill Hybels writes about 'holy discontent', which crystallises perfectly what the contented, discontented life looks like in practice. It's not that God hasn't given you a deep peace. It's not that your spiritual life is deficient, either. You can be full of peace and making good progress. But it asks a vital question: where is God at work in you now? What makes you put your packet of peanuts down, jump off the sofa and shout, 'it shouldn't be like that!'

If you've got a holy discontent at the moment: embrace it. Make it a cup of tea, take it out on a date, buy it a big fluffy bear with a sign round its neck saying something like 'forever yours'. Don't run from discontent, let God use it for His glory.

Being and becoming

I cannot stress strongly enough that God loves you as you are. He made you that way – like it or not – and like any master craftsman, when he stepped back, he took one look at you and went 'wow'! He also made you with a soul and a conscience, so that you, quite literally, are. A human being.

But, as we are all painfully aware, our being is not perfect, not even close. The major task of walking with Jesus through the rest of our lives is simply to become what we already are. We are already 'seated with Christ' as a spiritual reality, but the physical reality of our lives often does not reflect that. And so we are not just human beings, we are human becomings – living, little by little, more of the 'not yet' in the 'now'.

Or, to return to where we started, slowly learning to live in heaven before we die.

Rev Matt Trendall is Rector of Walton Churches Partnership, Milton Keynes.