The joyful sound ripples up and down the pews, then trails off in titters until another outburst fills the church. Laughter. F. Forrester Church, the buoyant 37-year-old minister of All Souls Unitarian Church on Manhattan's Upper East Side, is preaching on the subject, "Why Angels Can Fly," and he has the congregation in stitches. "You remember why the Devil fell from grace," he asks. "He fell on account of his gravity. By the same token, G.K. Chesterton reminds us, angels can fly because they take themselves lightly."

If Church's message is uplifting, however, it's not because it's lightweight. The son of the late U.S. senator and renowned orator Frank Church of Idaho, Church is rapidly emerging as an inspiring new voice for liberal religion. His autobiographical tribute to his father, Father and Son, was nominated for a 1985 Pulitzer Prize, and with the publication this month of a new book, The Devil & Dr. Church, a growing audience is beginning to hear the Word according to Church.

"I don't come thundering out of the pulpit with the quote-unquote truth," he says. "I am involved in a search, and all of my conclusions are tentative." His denomination, the Unitarian Association, has a distinguished intellectual heritage. With roots dating back to the 16th century, it was organized in the U.S. in 1825 (Ralph Waldo Emerson was an early member, as were Henry David Thoreau, John Adams, Clara Barton and Horace Mann). Unitarians are famous for doubting. As one joke puts it: "How do you get a Unitarian to leave the neighborhood?" Answer: "Burn a question mark on his lawn." Church's theology follows Unitarian tradition, which stresses the importance of ethical living and regards Jesus as an exemplary moral teacher while denying his divinity. As Church puts it: "God is not God's name; God is our name for that which is greater than all and yet present in each of us."

On social questions, Church firmly challenges the religious right on almost every issue, from abortion to AIDS to arms control. His lively sermons and personal warmth have attracted an even mix of Catholics, Protestants and Jews, many uncomfortable with the creeds of their birth. Explains Warren Bryan, a disaffected Episcopalian, "I've found a home here. His wit is beautiful and it's never a gag. He's a unique guy—and it's for real." Since Church's arrival in 1978 All Souls' membership has zoomed from 388 to nearly 1,000, and the congregation is now planning to install closed-circuit TV to handle the Sunday service overflow.

Church has also imbued the formerly staid All Souls congregation with a new spirit of community activism. His parishioners are constantly reaching out with new programs, including a soup kitchen, evening meals for the homeless and a campaign for peace. Shortly after ministering to one of his own parishioners who was dying of AIDS, Church had his congregation organizing a task force to help AIDS victims. For, although he chose the pulpit over politics, Church still looks to his father's example in his concern for others.

Six months after Forrest was born, his father, then 23, was told he had terminal cancer. In Father and Son, Church tells how his parents even considered double suicide until radiation therapy, at that time a highly experimental treatment, stopped the malignancy. When Church, who was raised a Presbyterian, was 9, his father gave him a Bible edited by Thomas Jefferson, who was a Unitarian. Jefferson's version of Jesus' life tossed out the miracles but kept the morals, and Church never forgot his father quoting Jefferson, "...for it is from our lives and not from our words that our religion must be read."

In 1966 Church entered Stanford University, where in his junior year he met his wife, freshman Amy Furth. Both became involved in the Vietnam protests centered in Stanford's inter-faith Memorial Church. "We really felt as if the whole world were on the brink of some cataclysmic change," says Amy. "I think that's really why we got married." She was 19 and he was 21. Following Amy's graduation, they entered Harvard Divinity School, where they both became Unitarians. She was named the youngest ever acting dean of students, while earning a master's degree in medieval studies. After years of academic indifference, Church plunged into scholarship at Harvard, burying himself in arcane theological works and learning Latin, Greek, Coptic, French and German. He wrote his doctoral thesis on the Gnostic gospel of St. Thomas and graduated magna cum laude, although he says, "Today I can't even understand my own footnotes." He was planning on a career in academia when All Souls invited him to visit for a weekend, all-expenses-paid interview. Up to that time he had preached only five sermons in his life, but he bowled over the congregation and was chosen as minister.

It remains to be seen whether Church's liberal theology can touch a wider public outside the educated, upwardly mobile members of All Souls, but Church believes there is a large middle group of faithful doubters, neither dogmatic believers nor unrepentant atheists, who are looking for leadership. "Recognizing the dangers of fundamentalist religion in this most pluralistic, divided, diverse world, I feel that our message is a saving message, because it respects the other person," he says. Everyone, he urges, should take up the challenge of life's question marks. Indeed, for many of his parishioners, there is more faith in Church's honest doubts than in others' pious certitudes.