Pope Francis is displaying an extraordinary style and passion that demands our attention. He addresses the needs of the poor, embraces outcasts, and loves those on the margins of society. In this recent "apostolic exhortation," The Joy of the Gospel, the pope raises a moral challenge to both his church and the world.

Like Dr. Martin Luther King Jr., Pope Francis calls upon people of faith to "go forth" to preach and practice their faith. "I prefer a church," he writes, "which is bruised, hurting and dirty because it has been out on the streets, rather than a church which is unhealthy for being confined and from clinging to its own security."

Pope Francis raises a profound moral voice against "trickle-down theories," which put a "crude and naive trust in the goodness of those wielding economic power." We have created "new idols," he warns, in the worship of money and markets. The result is that "human beings are themselves considered consumer goods to be used and then discarded." We have witnessed "a globalization of indifference," in which the poor are dehumanized and ignored, he writes.

Pope Francis' exhortation, over 50,000 words long, deals broadly with the church, the papacy and matters of the faith. He is not a revolutionary. He states that the priesthood will remain open only to men, that the Catholic Church's opposition to abortion will continue. But he directs new focus and passion to the growing inequality between and within countries, the stark contrast between the wealth of our technology and invention and the poverty of our ethics.

In this he addresses directly the plight of today's America. We suffer mass unemployment while the stock market hits new highs. Profits set records, but working people don't share in the rewards. The top 5 percent pockets literally all of the rewards of growth, while the remainder struggle to stay afloat.

This extreme inequality, Pope Francis writes, is the direct product of "ideologies which defend the absolute autonomy of the marketplace and financial speculation. ... A new tyranny is born" and with it widespread corruption and tax evasion among the most powerful. Money, the pope argues, "must serve, not rule."

This is not a secondary concern, but the heart of the mission of today's church. Pope Francis notes that just as the commandment says, "thou shalt not kill," we must say, "thou shalt not" to an economy of "exclusion and inequality. Such an economy kills."

He warns of the corruption and the ethical poverty of ignoring the poor. In our politics, poverty has become literally unspeakable. Politicians talk about defending the middle class, or "middle out economics." The poor are scorned as lazy or incompetent. Politicians vote to cut food stamp allotments, to cut unemployment insurance, even to cut back nutrition programs for impoverished mothers and infants, while they refuse to close the tax havens that allow multinational corporations and the wealthy to avoid paying taxes.

Too many politicians devote their energy to raising funds from the affluent and protecting their interests. They seek careers and fortunes, not public service. Pope Francis sees this as moral corruption, and calls for "more politicians who are genuinely disturbed by the state of society, the people and the lives of the poor."

At the same time, Pope Francis issues a stern warning to the complacent. Without justice, there can be no peace. Building up police and armaments offers no answer. Peace will come only when there is hope, and a committed effort to provide opportunity and justice to those who are locked out or pressed down.

Economic populism is not foreign to the Catholic Church and has been articulated by previous popes. But Francis' clear words and bold style make his message compelling. This is an authentic, world-changing gospel of good news. This is a return to the original gospel that Jesus taught. It seeks not pity for the poor but their emancipation. Churches cannot be silent in the face of growing inequality and desperation. People of faith must "go forth" and be willing to be "bruised, hurting and dirty" in the cause of justice. This is a charge all of us, whatever our faith, should take to heart.