"Giving praise and honor to God for bringing us together today," he began in thanks to the gathered congregation with the ease of a seasoned minister.

"We all made this journey for a reason," Obama said.

Obama's pilgrimage began two decades ago, when he took a job as a community organizer working for churches.

"I joined with pastors and lay people to deal with communities that had been ravaged by plant closings," he said. "It was in these neighborhoods that I received the best education I ever had and where I learned the true meaning of my Christian faith."

Obama the preacher touched the sacred visions of President Abraham Lincoln, who called a divided house to stand together, and Martin Luther King, who called for justice to roll down like waters and righteousness like a mighty stream.

"Today we are called once more—and it is time for our generation to answer that call," Obama said. "For that is our unyielding faith—that in the face of impossible odds, people who love their country can change it."

The senator spelled out a change-mission headed toward justice and concluded with a reference to "new birth."

Obama is not alone in giving a trial sermon to the national church. Others have given and will give sermons, hoping that their message will resonate with the citizen congregants.

Sen. Sam Brownback (R-Kan.) issued a pastoral letter, albeit via video and in a written statement in which he, too, recalled Lincoln's reference to a divided house.   

"Ours is a great nation and I make one pledge to you ... to use our greatness for goodness," Brownback began in his letter. "We are a great nation because our greatness is built on the foundation of fundamental goodness. If ever we lose our goodness, we will surely lose our greatness."

Brownback appealed to William Wilberforce, a member of the British Parliament and a Christian abolitionist who spent a lifetime to end the slave trade.

"A committed Christian who believed his faith should be a force for good in Britain and around the world, Wilberforce had two great passions: ending the slave trade and renewing the culture. Although his goals appeared impossibly lofty, both were achieved," Brownback said. 

After spelling out his agenda, Brownback said: "To walk away from the Almighty is to embrace decline for a nation. To embrace Him leads to renewal for individuals and for nations."

He concluded, "How much better we will be as we seek to live the Great Commandment to love God and one another."

Other presidential candidates have shied away from such explicit sermons, from substantive references to the Bible and historic Christians. 

Rep. Dennis Kucinich (D-Ohio) concluded his announcement: "The prophet Isaiah said, 'Without vision, a people perish.'"

Gov. Tom Vilsack (D-Iowa) referred to his mother's faith and God's intention for every child to have good educational opportunity.

Like Vilsack, Sen. Joe Biden (D-Del.) ended his exploratory video announcement with the obligatory, "God bless America."

One candidate's video announcement of an exploratory committee was devoid of a religious appeal: Sen. Hillary Clinton (D-N.Y.).

Gov. Mitt Romney (R-Mass.) formed an exploratory committee in early January without a formal announcement. Gov. Mike Huckabee (R-Ark.), a former Baptist preacher and seminary graduate, formed an exploratory committee a week ago.

Other likely candidates include Gov. Bill Richardson (D-N.M.), Sen. John Edwards (D-N.C.), Sen. John McCain (R-Ariz.), Mayor Rudy Giuliani (R-N.Y.).

Who will preach the next trial sermon to the national congregation?

Robert Parham is executive director of the Baptist Center for Ethics.