Pope Francis can heal the Catholic Church

A homeless man taught me a lesson over Christmas. His name was Marczin. The unemployed truck driver from Poland currently sleeps in a Vatican porch with three other itinerants and his dog. Their bags, sacks and blankets constitute a modern crib on the edge of St Peter's Square. They are those for whom, today in Rome, there is no room at the inn.

A few days before Christmas it was the Pope's birthday. Francis was 77. To celebrate he invited Marczin and his homeless comrades to a breakfast party. The news went big in the Italian press as another of the new pontiff's audacious "church for the poor" gestures. But the next day the Newsnight crew with which I was filming found the men incapably drunk in St Peter's Square. The next night they were sleeping rough in the porch again.

Pope Francis's gestures have won the hearts of people, religious and non-believers, all across the world. This is the man who rejected the lavish trappings of papal office to live in a hostel. He hugged and kissed a man suffering with the repellent elephantine skin malformations of Recklinghausen's disease. He donned a red nose for two newlyweds who use clown therapy in their work with sick kids. He ruffled the hair of a little boy who invaded the stage and clung to the papal leg despite repeated attempts by aides to remove him.

He has said the right things too. Invited to condemn gay Catholics he replied: "Who am I to judge?" He has been ferocious in his denunciations of unfettered capitalism. He has warned new bishops to avoid the "psychology of princes" and denounced clerical careerism as "a form of cancer". He has told religious orders to turn their under-used convents and empty monasteries into shelters for refugees.

And yet, for all that, Marczin still has no bed and no job. There was no contradiction in that to Marczin. Was breakfast enough? I asked him. "Yes, there were herrings and everything," he replied, misunderstanding my question. Couldn't the Pope find him a hostel or some work? Marczin replied: "No, that's not his job. Anyway we like to move around. And the Pope has millions of other people to look after – with bigger problems."

It was an interesting corrective. After all, the Catholic Church is a body that's big on sacrament – which, translated from theological jargon, is merely the insistence that outward signs and symbols are freighted with a deep internal significance. It's not about style or substance, Marczin told me. The medium is the message. The style is the substance. Gestures that change the way we see the world are what the Gospel is all about.

Perhaps that is why the new Pope's first official trip outside Rome was to Lampedusa, the remote Mediterranean island between Sicily and Tunisia that has been landfall for thousands of desperate African migrants seeking a better life in Europe. Pope Francis said Mass there using a wrecked boat as an altar. "In this globalised world, we have fallen into globalised indifference," he said there. "We have become used to the suffering of others."

There was something of the same about his Christmas messages. It was predictable enough that he should call for peace in the world's newest conflict in South Sudan; in Syria, Iraq and between Israelis and Palestinians; and in forgotten places like the Central African Republic, where things are going from bad to worse out of sight of the world's cameras.

But he went further in asserting that true peace is not a balance of opposing forces or a façade to conceal conflict and division. "Peace calls for daily commitment … from every man or woman who hopes for a better world," he said. It meant commitment in individual lives, in families, cities and nations. It required an opening of hearts hardened by pride, deceit and self-seeking – a task in which, he said he invited atheists to join with believers.

Change is, of course, about more than words. Francis has demonstrated an understanding of that in practical action. He has instituted reform at the scandal-hit Vatican Bank, closing more than 600 suspect accounts. He has set up a commission to deal with paedophile priests. He has appointed another to reform the sclerotic Roman bureaucracy and turn its officials from masters to servants of the wider church. He has ousted conservative clerics from key positions. All this has liberated many Catholics from decades of internal exile within their church. And it has suggested to outsiders that the insights of religion are not for the cloisters but for the market square.

But change is about words and gestures too. The homeless truck driver Marczin understood that intuitively where I had not. So toon did the former Catholic priest, James Carroll, who wrote recently in The New Yorker about watching Francis pray over a man with a brain tumour in the St Peter's Square crowd. Carroll wrote: "I realised, as the Pope pressed his hands on the bowed head of the stricken man, that curing and healing are not the same thing. To cure is to remove disease. To heal is to make whole, and wholeness can belong as much to the infirm as to the healthy."

The Pope himself articulated something similar. Structural and organisational reforms are important, he said, but the first reform must be in attitude. Priests must become those "who can warm the hearts of the people".

Though there were no cameras present, Pope Francis spent twice as long visiting sick kids and their parents in Rome's main children's hospital at Christmas as he did on all his messages and public worship combined. "Things from the heart," as he said on another occasion, "don't have an explanation."

'Pope Francis – Untying the Knots', by Paul Vallely, is published by Bloomsbury