Many years ago when I was at school, children tended to divide into two groups. There were those who loved sport, who would be outside on the football field or inside in the gym at every opportunity, and those who hated sport, who used any excuse to avoid ever going near the football field or the gym.  If you are wondering which group I fell into then suffice to say I was very creative with my excuses!

Those who loved sport loved it with a passion, and those who hated sport hated it with an equal passion. But I don't think those childhood emotions necessarily continue for the rest of one’s life. There are plenty of people who hated playing sport themselves but who have become avid attendees at the local gym, or who have discovered a sport that they love, like golf or darts, or who have become ardent supporters of the local football team. And there are many people who sit at home in the afternoons, eager supporters of snooker on the television.

Even those who have no interest whatsoever in sport, know the importance of exercise to keep fit and healthy, and the importance of training for sportsmen and women. Those who compete in the London marathon train for months beforehand, because they know they'd never be able to run twenty-six miles unless they gradually worked up to it.

Paul the Apostle was a city dweller and therefore unlike Jesus who had a rural upbringing, Paul never uses images from the countryside to illustrate his points. Paul uses images from the city to illustrate his points; images of the law courts, the sports field and the army. These are all images, which would have been familiar to cosmopolitan city people rubbing shoulders with Greek and Roman influences.

In today's reading from Corinthians Paul uses images from athletics and the boxing ring to emphasise the need for Christians to go all out for Christ, just as if they were training to win a special sporting event.

In our present society, competition sometimes has a bad press. Children are no longer encouraged to compete against each other in quite the way they were encouraged years ago. And there's something to be said for this new attitude. Children need to experience both winning and losing, but it can only harm children's development if they constantly win and never experience failure, or if they constantly lose and experience nothing but failure.

But it isn't like this in Christianity, for everyone who trains wins the ultimate prize. There are no losers in Christianity, and indeed, Jesus himself was particularly concerned to reach out to any who might consider themselves to be a loser or to any whom society considered to be losers.

Exactly how do we train for this Christian life? Paul makes it sound like unremitting hard work.  Because those who hope to win a race must spend hours and hours in training, with no guarantee that they'll come away with anything at the end. The point he's making is that Christianity demands our whole life. It isn't a part-time hobby, just to be followed at weekends or when there's nothing else to do, but is life itself and is therefore all consuming.

We receive Christianity's rewards in the same measure that we give our lives to God. Those, for whom Christianity is their whole life, receive huge rewards because they experience the presence and power of God in their lives. Those who keep God out all together can't enjoy the rewards and gifts he offers, because they won't allow God into any part of their lives. And the rest, that is, those who allow God into part of their lives, receive some reward but not everything they could receive, because they're unable to allow God to be completely present within them. They need to keep some control in their own hands and are unable to hand over complete control to God.

Most of us are probably in this latter category, since we believe Jesus himself to be the only person who has been able to allow God total and utter control of his life without holding anything back. And his prize was amazing powers of love and healing and an astounding resurrection after death in which he was able to revisit this life for a time.

We have been promised exactly the same. Jesus told his disciples that they would be able to do even greater things than he himself had done, and Paul tells us that through Jesus, we too are inheritors of God's heavenly kingdom. The most obvious difference seems to be that Jesus was able to return to this life for a time after his death, and we aren't able to do that.

But Paul tells us in today's reading that it's no good taking a little spiritual exercise now and again, when we happen to feel like it. "I do not run like a man running aimlessly; I do not fight like a man beating the air," says Paul.

Unlike physical exercise, spiritual exercise largely, but not completely, consists in doing nothing. We need to read the Bible regularly so that we become steeped in scripture, in God's word. We need to pray regularly both in our own regular quiet time and with others, for Christianity is a communal religion. But most of all we need to give time and space to God, so that we can hear what he has to say to us.

So as much as anything, spiritual exercise consists in doing nothing but waiting upon God. This can be achieved in just ten minutes a day, sitting in a quiet place and focussing the mind upon God, maybe by reading a verse of scripture over and over again so that it seeps into our soul, and some people enhance the experience by using quiet music.

Methods of opening up the self to allow God to come in differ with different people. There is no right or wrong way, just different ways. The rightness or wrongness lies in the regularity of the spiritual training. Haphazard, now-and-again training doesn't build spiritual muscle, doesn't lead to spiritual health and doesn't win the spiritual race.

Regular training, however brief and however inadequate it may feel, does build spiritual muscle, it does lead to spiritual health and it does win the spiritual race. In the end, if Christianity is our life rather than our hobby, all we have to do is make a very little daily effort to open ourselves to God. We can rely on him to come in to us and to do the rest. God will redeem our inadequacies and give us rewards infinitely more glorious than anything we can ever imagine.

So even if you hate sport with a passion, like I do, it's probably a good idea to follow Paul's advice and start some spiritual training straight away!