I DO not know Bishop Stephen Cottrell, but I have had the pleasure of hearing him preach twice, and he was bold and beckoning in equal measure. His writing follows suit. It is invitational, assuredly seeking to entice the reader out of an unreflective nine-to-five existence into the spiritual adventure of being an apprentice of Christ.

This is a book that Cottrell has wanted to write, he says, for more than 20 years. His love of the work of the artist Stanley Spencer (1891-1959) has relentlessly deepened over that time, and he expresses it here with a spiritual breathlessness that is infectious and transformative.

He does it by taking a good hard look at five paintings from Spencer's series of works Christ in the Wilderness, and asking us what we see there. Unless you intend to travel to the Art Gallery of Western Australia, in Perth, to see the originals, you could do no better than use this short guide to these extraordinarily affecting paintings, with its beautiful reproductions, as a prayerful key to unlock the works' subverting theological potential.

At the top of a house near Swiss Cottage, away from his home village of Cookham, in Berkshire, Spencer locked himself away in solitude and began to work on the Christ in the Wilderness series. He described that period as a time of "finding myself after being lost for such ages"; and the still, distilled monumentality of Christ in the paintings bears witness to the stripping-away and consequent rebirth of the artist's inner life and discipleship.

You sense the snowfall in the soul which has changed the air that the artist inhabits. Painting was, he said, a way of saying "Ta" to God. The series has been called "reparative", and, as such, it is an ideal companion for a Lenten journey. This is a book to make you rediscover your sight in order to gain a vision. Here, theology becomes a visual art, not a verbal science - a source of threads to pursue rather than to tie up.

Spencer once said that he was "on the side of angels and dirt". This incarnational impulse is at work in the Christ in the Wilderness series, where Christ is given an original personality, young and solitary in the desert, entranced by animals and plants - many of which figure in his consequent teachings. The roots of the trees are seen above ground in many of the paintings. They frame the rootless, nomadic Christ, who is learning where the heart's home lies.

The first painting that Cottrell looks at is of Christ rising from sleep in the morning. Christ raises his arms like a steeple towards heaven, his robe panning out in a crater (or a wartime shell-hole that Spencer recalled), making him resemble a flower turned to the warmth, and opening up in the sunlight. It is a portrait of intimacy, freedom, energy. Cottrell, admitting he finds prayer hard, learns here that "the purpose of prayer is praise: not because God needs our thanks, but because without God there is nothing."

To see a fat Christ is as rare as seeing a laughing one, but in Consider the Lilies Spencer depicts him as mountainous in comparison with the daisies (not lilies) that he contemplates. Cottrell notes that this Jesus is playful, "huge and humble", godlike. Whereas lilies call for attention, in church or posh hallways, daisies are overlooked, or considered problematic in our neat lawns. Jesus relishes their beauty, and, at the same time, challenges the sad fact about human beings that "when it comes to the present moment, we're not present".

Cottrell cleverly refers us to the words of Nadine Stair: "If I had my life to live over . . . I'd relax, I would limber up. I would be sillier than I have been. . . I would do more walking and looking. . . I would pick more daisies."

The Scorpion is a haunting work. We see a sad, pitying Christ filling the picture, with a scorpion gently held in his palm, stinging away in places where nails will later be hammered. This painting adds shadow to the series, the cost of encountering the darkness of the world sharply exposed. Cottrell observes Jesus positioned as if he is giving birth, overtones of dawn on the horizon. The power of Christ here is not a force that crushes scorpions underfoot, but something that "cherishes the very thing that could kill him".

The last two paintings depict Christ's spending time with foxes and hens. Spencer believed that to reach heaven is the relief of "being safe again, being home, where one belongs". Grief is love that has become homeless. The foxes burrow around Jesus as he lies in a cross shape, making home with them in a placeless place.

Then, a sleepy Christ watches a hen with her chicks. A sparrow flies into the scene - there is room for everyone - and the freedoms and protections of relationship are encircled by his body. For Cottrell, this image is full of reassurance and promise. Any followers of this Jesus are going to have to be brave enough to form a Noah's ark of a community, where every weird and wonderful animal will have to budge over to make way for another.

If you have written off contemplation as above your faith grade, better suited to holy people, then this book makes you think again. Spencer saw what he called "sacred quality in most unexpected places". The poet Les Murray has written that God is in this world as poetry is in the poem. Cottrell picks up his glasses in this book to help us read this world better.

The gospel disorientates our prejudices and first impressions, leading us back to a heartland that is both strange and familiar. Spencer captured this truth in his life's portrayals of homely resurrections, a nature-loving Christ, and mirrored impressions of the self. Cottrell's book entices us, with humour and insight, to take our Christian vocation of living in the poem of creation more joyously and generously, as if we had come out of a desert.

The Revd Mark Oakley is Canon Chancellor of St Paul's Cathedral.

Christ in the Wilderness by Stephen Cottrell is published by SPCK at £9.99 (CT Bookshop £9 (Use code CT628  ); 978-0-281-06208-9.

CHRIST IN THE WILDERNESS - SOME QUESTIONS

Why is Stephen Cottrell so inspired by Stanley Spencer's work?

"To look at these paintings is itself an invitation to enter the desert through the doorway of your imagination" (page 17). How important is the desert of your spirituality?

Did you resist the temptation to read the words before taking a good long look at the paintings?

How can art help us to pray?

Which picture did you find most powerful? Which of the chapters did you find most helpful?

Why do many Christians find playfulness so difficult? What can be gained from it?

Stanley Spencer's depiction of Jesus is different from the traditional ones. Which aspects of his character can be seen in the paintings in a new light?

How did Spencer's faith inform his painting?

"The sense of the presence of God in all things and the possibility of honouring God in every action is evident in the paintings" (page 96). How is this depicted? If you visualised it, what would it look like?