I was fascinated by the first photograph of a black hole. No, I don't understand the physics but it spoke to me about the grandeur of the universe and in doing so strengthened my belief that the universe is made and governed by an almighty God.

It also reminded me of the astonishing ability of the human mind to understand such things and confirmed my belief that as human beings we are made in God's image.

Yet what I find intriguing about black holes is not what they are but their power as a symbol or a metaphor. The release of the image on the very day of the latest major twist in the seemingly endless Brexit saga meant it was inevitable that the media was full of the black hole as an image of the British predicament. Well, perhaps. But the black hole is an image that has a wider significance.

The idea of an object so powerfully inward-focused and destructive that it draws everything into itself and then gobbles it up is something that has echoes in many areas of life. It seems that if the phenomenon of a black hole didn't exist, it would surely have to be invented!

As I thought about black holes in this run-up to Easter, I found myself contrasting the idea of the black hole with the cross. There are comparisons: the black hole looks inward while the cross points out, takes in while the cross gives out, brings destruction while the cross brings life.

Those opposing images can be seen as principles that govern our lives. Do we take in or do we give out? Is our priority our own well-being or that of others? Do we focus on the fulfilment of our own desires or the concerns of those about us? It seems as though each of us must choose what principle we live under; to decide whether the geometry of our lives is the shape of the cross or the monstrous and ever hungry circle of the black hole.

These two opposing principles are particularly important when it comes to the Christian involvement in society. Throughout history, Christians (and Christian organisations) have faced the choice of looking inwards or looking outwards. Jesus constantly encouraged his followers to face outwards; to be salt and light (Matthew 5:13–16) and to go into all the world. The good news of the gospel is not for our own benefit but for those who we live amongst.

This contrast between the black hole and the cross should make us think. Even if we are a Christian it's tempting, especially at a time when the world seems hostile, to adopt a privatised religion and focus on being blessed or enjoying God. With that comes the danger that the focus of our life points inwards not outwards.

The fact, too, is that now is not the time when we can afford the luxury of spiritual self-indulgence. We live when the influence of Christians on society is needed. There is a bleak moral landscape around us where there is no ultimate right and wrong, where truth is what the media says it is, where mercy and kindness are seen as weaknesses to be rejected, and where money, sex and self-fulfilment are portrayed as all that life is about. These views are not just simply mistaken illusions; they are beliefs that poison lives and leave a bitter legacy. The results are a society that increasingly seems to grow crueller, more unjust and more empty.

The uncomfortable truth is that we who are Christians must share our faith and let it influence our society, both for our sake and its. We must speak out on biblical values and principles, must challenge lies and must oppose wrong world-views. We must seek a Christian life that does not merely love God but loves our fellow beings too. We must either look outward and be involved with others or let ourselves be dragged in to that destructive and potentially inescapable black hole of the self-centred existence.

But it's not easy: the principle of the cross is life-giving but carries a price. All too frequently recently I have found the following phrase echoing in my head: 'It is better to stand with God and be judged by the world than stand with the world and be judged by God.' It's hard to argue with that.

We all need to think about how we can get involved. It's tempting in a world that seems to have little time for Christianity to retreat from it, but in doing so we take a step away from the principle of the cross and edge closer towards the black hole. Can I encourage you this Easter to think about how you relate to the world you live and work in? Pray about how you can be involved, let yourself be challenged by Scripture, set as a goal the influencing of your world for good.

And, specifically, if you are aged 18 to 30 can I recommend that you look at the forthcoming Wilberforce Academy which will take place on 9th–14th September 2019 in Oxford? It is a unique opportunity to spend a week grappling and engaging with these issues. It is significantly subsidised, has excellent speakers and is life-transforming. 

Finally, the black hole and the cross are not just symbols of the priorities we choose for ourselves but they also apply to our future. One astronomer referred to the imaged black hole as 'the gates of hell'. I'm sure it was merely an arresting phrase but they may have spoken more truly than they meant. To drift towards the black hole of seeking yourself leads to eternal loss; to choose the cross is to gain the resurrection life. Let's make the right choice!

J John is an evangelist and director of the Philo Trust