“God is working in history to bring about this new age.” Is this Pat Robertson speaking? Or perhaps the Reverend Jerry Falwell? The language of religion in this country has been so thoroughly taken over by conservative Christians that it comes as a shock to learn that these were the words of Dr. Martin Luther King Jr., seven months into the Montgomery bus boycott.

In his passionately argued book, “The Beloved Community” (Basic Books, 292 pages, $26), Charles Marsh, the director of the Project on Lived Theology at the University of Virginia, quotes this speech for a purpose. He wants readers to understand that Christian faith was at the heart of the civil rights struggle. For a time, this movement motivated millions of Americans to rise up and be counted for justice and reconciliation: black Americans who refused to be intimidated any longer by the violence of American racism and white Americans who refused to sit by and remain silent accomplices.

On several counts Mr. Marsh is writing a revisionist history of the civil rights struggle and the continuing quest for racial justice. He aims to seize civil rights history from secularists and reclaim it for Christianity by highlighting the “theological drama” at the heart of the movement. At the same time, he disputes the belief that the civil rights movement was one of the most successful mass mobilizations in American history.

“Life is a continual story of shattered dreams,” King said the month before his assassination. Mr. Marsh draws from this the conclusion that, by 1968, the vision of beloved community that had animated civil rights activists lay in ruins. According to Mr. Marsh, the reason was a loss of faith, a younger generation “emptied of the dream of God.”

Above all, Marsh wants to rescue the post-civil rights era from neglect by reminding us that since the 1960s a new generation of Christian activists has quietly devoted their lives to the dream of community. These unsung heroes are pursuing an agenda for change “more radical than any advanced by the civil rights movement.” At a time when individualistic market values seem to have triumphed in America, when political leaders invoke God to justify war between nations, Mr. Marsh finds hope in these scattered social experiments.

All this makes for inspirational reading. Mr. Marsh offers a vivid picture of King’s spiritual growth in the course of the Montgomery boycott. He recalls the courageous work in Mississippi and Georgia of the young activists in the Student Nonviolent Coordinating Committee. Their style of “incarnational organizing” sent them into communities across the South, where they put themselves at the service of local people, most of whom were desperately poor.

The second half of the book moves on to individuals and organizations who, unlike King and the Southern Christian Leadership Conference, have not been engraved in our nation’s memory. Central to Mr. Marsh’s account is the story of John Perkins and his Voice of Calvary mission, toiling away in Mississippi to bring hope to African Americans and to bring reconciliation across racial lines. But there are other figures as well: Mark Gornik in Baltimore, Gene and Jackie Rivers in Boston, Russell Jeung in Oakland, and Ray Rivera in the Bronx. These are the true faith-based initiatives in America today, and Mr. Marsh finds it appalling that our national leaders refuse to endorse them.

It is hard not to admire the men and women whom Mr. Marsh writes about. But, admiration aside, he did not persuade me that these experiments in Christian activism provide hope of building a just society. And he did not convince me that they and their leaders offer a better model for social transformation than does the work of the civil rights movement and its exemplar, Martin Luther King, Jr.

King’s greatness did not come just from his ability to articulate on a stage larger than his pulpit the spiritual traditions of African American Christianity. Nor was it about his claim that the true Christian must live out his and her ideals. As Bayard Rustin, an associate, often commented, King broke with the “come-to-Jesus” style of Christianity that dominated the black church. He also insisted on far more than doing good deeds: King’s spiritual understanding led him to advocate political engagement, a commitment to remake government and social institutions in the service of racial and economic justice.

By contrast, the Christian community-development activists whom Marsh holds out as his hope for the future remain rooted in a very old American tradition of religious perfectionism, traceable as far back as John Winthrop and his Puritan “city on a hill.” As one of Mr. Marsh’s contemporary heroes says, “Communities like ours … are places where Christians are learning not so much how to solve the race and other social problems but how to be truly church.” Mr. Marsh’s Christian models seem, in the end, to share the ethic of a secular therapeutic culture obsessed with feeling good about itself. Place the outlook of these Christian activists alongside the insistence of King and other civil rights leaders that results matter and there seems to be no contest over whose experience offers more useful lessons to those yearning for justice and community.

Mr. D’Emilio is the author of “Lost Prophet: The Life and Times of Bayard Rustin” (Free Press).