It’s only eight months since Jorge Mario Bergoglio ascended the throne of St. Peter, and already it’s clear that he’s determined to be a very different kind of Pope. After the bookish and remote Benedict, Pope Francis is a refreshing model of modesty — living in a simple Vatican guest house, travelling in a Ford Focus, and kicking a German bishop out of his palace for outrageous spending.

Much of the change is symbolic, though no less welcome for that. But now Francis has made it plainer than ever where he intends to take the Catholic Church – and it turns out to be a full-throated challenge to global capitalism. Far from pulling his punches on the injustices of what he calls “the idolatry of money,” the new Pope this week issued a blunt critique of the market economy.

Listen to what Francis has to say in his first major official statement as Pope, a 5,000-word document entitled Evangelii Gaudium (the Joy of the Gospel): “Just as the commandment ‘Thou shalt not kill’ sets a clear limit in order to safeguard the value of human life, today we also have to say ‘thou shalt not’ to an economy of exclusion and inequality. Such an economy kills.”

And further: “How can it be that it is not a news item when an elderly homeless person dies of exposure, but it is news when the stock market loses two points?”

“Some people continue to defend trickle-down theories which assume that economic growth, encouraged by a free market, will inevitably succeed in bringing about greater justice and inclusiveness in the world. This opinion . . . expresses a crude and naïve trust in the goodness of those wielding economic power.”

On the church itself, he pointedly writes: “I prefer a church which is bruised, hurting and dirty because it has been out on the streets, rather than a church which is unhealthy from being confined and from clinging to its own security.”

These are strong points, forcefully made in plain language. If Pope Francis means what he says — and there is every sign that he does — then the cossetted Vatican office-holders are deservedly in for a rough ride. More importantly, those in the church who fight for social justice will be emboldened to speak out more loudly. To his credit, Francis has put himself squarely in the camp of those worried about the persistence of poverty amid plenty, and the widening gap between rich and poor.

None of this is strictly new, of course. Modern Catholic teachings on social justice have stressed the perils of unbridled capitalism since at least the 19th century. But they have usually been downplayed by the church hierarchy or, more recently, obscured by fights over moral issues.

That’s one of the most important parts of Francis’s message. Once again, he is telling Catholics not to obsess about other people’s sex lives. He doesn’t back away from traditional church teachings on abortion and sexuality, which will upset some people. But he refuses to make them the focus of his papacy. As he told a recent interviewer from an American Jesuit magazine: “The teaching of the church is clear, and I am a son of the church, but it is not necessary to talk about these issues all the time.”

This is an encouraging turn for a church that, despite all its problems, still claims more than a billion adherents around the world. To be relevant it needs to speak to the issues that are upper-most in the minds of its followers, and most Catholics are to be found in countries where poverty and inequity – not sexuality – are the most pressing problems of the day.

In rich countries, as well, the key political divide is between those who worry about rising inequality, and those who dismiss it as an inevitable consequence of the global economic system. Pope Francis has picked his side in this debate, without apology. Quite rightly, he has chosen to take the part of those who believe that, in his words, “Money must serve, not rule.”