The former governor offered up thanks to Pastor Craig Oliver who, Barnes said, was there for him during a difficult time.
"We were in the midst of changing the flag," Barnes drawled.
Murmurs of approval rippled through the crowd of black worshippers, who recall the racially charged battle Barnes led as governor nine years ago to strip the Confederate battle symbol off the state flag. Message delivered, Barnes returned to his pew as the choir revved up again.
Black voters comprise about half of Democratic primary voters in Georgia. And they're being courted aggressively by the seven men seeking the Democratic nomination for governor.
The jockeying has been particularly intense between Barnes, the Democratic front runner campaigning for his old job, and Thurbert Baker, the state's attorney general running to become Georgia's first black governor.
Barnes has lined up much of the state's black political machine - including former Atlanta mayors Andrew Young and Shirley Franklin. On Tuesday, just a week before the primary, he offered a fresh show of support - appearing arm-in-arm with a few dozen black pastors who prayed for a Barnes win next week.
Baker has his own share of black supporters and this week he upped the ante by announcing the endorsement of former President Bill Clinton, who has enjoyed strong support from the black community.
DeKalb County Sheriff Thomas Brown, a key Baker supporter, argues that while Barnes has backing from civil rights icons of the past, voters who watched Barack Obama become the nation's first black president may have their own designs.
"Coming off of the Obama election there are going to be a lot of people who have said the are going with Roy Barnes but when they get behind that curtain and get ready to vote they are going to ask themselves, 'Do I want to be a part of history and see a different Georgia like we see a different America?'" Brown said.
There's one problem with that theory, according to Emory University political science professor Andra Gillespie.
"Thurbert Baker is no Barack Obama," Gillespie said. "He is not in that young, telegenic, new wave of black leaders."
Gillespie, who wrote a book on black politics, said black voters tend to be pragmatic and that Barnes has looked like a sure bet since getting into the race.
And the fight over the flag, which helped lead to Barnes' defeat in 2002, could help him this time around, especially in the primary.
"In Georgia, you have a (former) white governor who took a hit on race and felt the consequences of it," Gillespie said.
That battle still resonates with Bishop Eddie Long, leader of the New Birth Missionary Baptist Church, a 25,000-member megachurch in suburban Atlanta.
"It matters to me that he is someone who put it all on the line to do what was right for the state," Long said.
Barnes also won fans in the black community by taking on the defense of the state's voter ID law - which critics say disenfranchises poor and minority voters - for free.
But as a state senator, Barnes in 1984 voted against final passage of a bill that would have created a state holiday to mark the Rev. Martin Luther King Jr.'s birthday.
"My people are just not for it," he said at the time, according to the Marietta Daily Journal. Barnes has since said he regrets that vote.
Baker has his own issues in the black community. He was assailed by black leaders in 2007 when he appealed a court's decision to release Genarlow Wilson, a black teenager serving a lengthy prison sentence for consensual oral sex with another teenager.
"I thought that was wrong," said Pastor Donald Battles, a Baker supporter. "But I think he has redeemed himself."
Battles said he was particularly impressed with Baker's decision to stand up to Gov. Sonny Perdue and refuse to sue the federal government to overturn the new health reform law.
"I think he could make history and show that Georgia has put its past behind," Battles said.
Supporters of the attorney general also note that for all Barnes' talk of changing the flag, it was Baker who introduced legislation in 1993 to erase the Confederate symbol, almost a decade before Barnes took up the fight.
In addition, it's a "tall order" to ask black voters to cast a vote against a black candidate, said Rick Dent, a veteran Democratic political strategist who has worked on campaigns around the South.
"Historical data is very clear that white voters vote for white candidates and black voters vote for black candidates," Dent said.
The other Democrats seeking their party's nomination are House Minority Leader DuBose Porter, former Georgia National Guard Commander David Poythress, state Rep. Randal Mangham, former Ray City Mayor Carl Camon, businessman Bill Bolton. Mangham, of Decatur, is the only other black candidate in the race but is considered a longshot.