For the Rev. Mike Huckabee, the podium is never far from the pulpit. Last month, just as the former Republican governor of Arkansas was unexpectedly rising in the Iowa polls, he was invited to deliver a Sunday-morning sermon at the DFW New Beginnings Church. An evangelical Christian congregation in the suburbs of Dallas (a three-hour drive from the Texarkana, Ark., church Huckabee led in the 1980s), New Beginnings is different from other megachurches in the South. It calls itself a "multicultural" ministry that upholds the Judeo-Christian tradition. The pulpit is adorned with a crucifix inside a star of David. A scattering of "messianic Jews" in the congregation wear yarmulkes. Its message is a blend of theology and self-help. God, the church Web site says, "wants to release the inner winner in you."

As it happens, that is a theme now very much on Huckabee's mind. All his life, he told the congregation as he casually paced the thick red carpet, God has found ways to point him to where he is today. An ordained Baptist minister, Huckabee immediately won over the crowd with a typically self-deprecating joke. "Are you one of those Baptists who think only Baptists go to heaven?" he said a woman once asked him. "No, ma'am," Huckabee said. "I don't think all the Baptists are going to make it myself."

Huckabee, who gave his first sermon as a teenager and got his start as an assistant to a televangelist, wasn't just playing at preaching in Dallas. He didn't take on that awkward way politicians have of speaking in church—drawl artificially deepening, voice dramatically quavering. He was entirely at ease. Huckabee never uses notes when he speaks, yet he covered a lot of Biblical ground in his talk, which centered on God's way of creating opportunity from adversity. He started out with the Old Testament story of Joseph and his brothers; touched on his own Everyman roots as a once poor kid "one generation away from dirt floors and outdoor toilets"; dipped into Romans 8:28 ("For we know that all things work together for good to those who love God …"), and gave "personal testimony" about how adversity in his own life has made his faith stronger. "You don't know that Jesus is all you need," he said, "until Jesus is all you've got." When he was done, the congregation gave him a standing ovation.

It has become a requirement for presidential candidates, Republicans and Democrats alike, to make a public declaration of faith. Some are more comfortable doing it than others. Rudy Giuliani, never a churchgoer, says his bout with prostate cancer made him more spiritual. Mitt Romney has struggled to find the right words to describe his lifelong religious convictions without alienating those suspicious of his Mormon religion. But for Huckabee, Christian faith is not merely a talking point—it is the talking point, the basis for his claim to lead. "Faith doesn't just influence me; it really defines me," Huckabee says in a TV ad now running in Iowa. "I don't have to wake up every day wondering, 'What do I need to believe?' " Just in case his meaning is not clear enough, the words CHRISTIAN LEADER flash on the screen in capital letters.

On the campaign trail, Huckabee quotes Scripture so often that his stump speeches themselves could be mistaken for sermons. He has spent less than $400,000 in Iowa, compared with Romney's estimated $7 million. In a recent speech at Liberty University, the Baptist school founded by Jerry Falwell, Huckabee said his surprise surge in the polls was the result of divine intervention. "There's only one explanation for it, and it's not a human one," he said. Paraphrasing Mark 6:41, Huckabee remarked, "It's the same power that helped a little boy with two fish and five loaves feed a crowd of five thousand people … There literally are thousands of people across this country who are praying that a little will become much, and it has, and it defies all explanation." At another campaign stop, Huckabee was a young David, "putting that little smooth stone in a sling" and taking aim at Goliath—played by, you guessed it, Romney.

In Iowa, Huckabee's carefully cultivated persona as a kind, thoughtful man of unshakable faith is winning many converts. A long shot just a few months ago, when he was trailing in the low single digits, Huckabee has slowly amassed a sizable lead over Romney, once the double-digit front runner. In the new NEWSWEEK Poll, Huckabee is the top pick among 39 percent of likely GOP caucusgoers, compared with Romney's 17 percent.