The teenage boys writhed with suppressed giggles as the prayer went on.
The prayer patrol are challenging young people on the streets
"Bless them, Lord! Protect them! May they never pick up a gun! May they never pick up a knife!"
When the four solemn women uttered their final "Amen!" and re-opened their eyes, the boys were already disappearing down the street at speed, guffawing and throwing mock punches.
The Prayer Patrol is an unconventional attempt to fight crime.
The women, led by the Reverend Dawnecia Palmer, her curls tumbling from beneath a felt cloche hat, walk through Bristol's most deprived neighbourhoods almost daily, blessing passers-by and praying over the willing.
St Paul's has the tired look of a deprived community, with plentiful graffiti, metal cages across shop windows and nailed boards where windows haven't survived.
In recent years, it developed a reputation as the city's crime and drug capital.
"It was so volatile in 2003," the Reverend Palmer told me. "A lot of gun crime, a lot of gangs. The police came out with guns."
She pointed to a street corner. "There'd be riot vans there."
"So I told the police, if we recruited people and put them on the street and they took their boys off, crime would be reduced by 50%." She brandished her New Testament at me, adding: "We've got our weapons here!"
After the crisis of 2003, the armed police presence was reduced.
In the hour we spent on the streets, we didn't see any police officers - just the four women, clad in luminous yellow jackets with the words "Prayer Patrol" in place of "Crossing Attendant" or "Police".
Further down the street, a young man, studded with metal, watched from the doorway of a shop selling brightly coloured wigs.
A few years ago, he said, "dealing in the area was getting a bit blatant".
I asked if the attempt to deploy large numbers of armed police had helped.
"All it did was clear people out from the street and as soon as the police were gone, they're back out," he said.
"People here are quite close knit and keep things quiet. People don't want to talk to the police. They don't want to get involved."
But he did approve of the Prayer Patrol. "The sight of them out there makes people feel safer," he said.
A middle-aged passer-by, Kay, pointed across the park.
"There's a gang of them there, doing drugs at the moment," she said. She too was reluctant to "get involved" by calling the police. "I just go in and stay in," she said and scurried off.
Police confirm that organised gangs, many involving visitors from Jamaica, actively target Bristol. Dealing in crack cocaine is rampant.
They responded by launching a major project called Operation Atrium, an attempt to tackle drug-related crime in conjunction with local communities.
Julian Feeney used crime to feed his drug habit for over two decades
Julian Feeney is a recovering addict who, for 25 years, used crime to feed his growing dependency on crack cocaine, heroin, amphetamines and other drugs.
He started taking drugs when he was just 13. Sniffing glue and aerosols and drinking cider, he said, gave him a feeling of belonging, after years of failing to "fit in", either at school or home.
By his late teens, he was part of a gang, stealing from cars, breaking into factories and shoplifting to buy drugs. By his early 20s, he was selling drugs too.
Through his 20s and much of his 30s, he made several unsuccessful attempts to stop taking drugs, especially after fathering a child.
But he became increasingly dependent, increasingly desperate for money and was constantly in and out of jail.
He finally entered a treatment centre two years ago, after warnings from friends that he was going to die. Life as an addict, he can say now, was "a permanent downer".
Today he is training to be a counsellor and mentor to others trying to end drug and alcohol abuse. He says the emphasis in tackling drug-related crime has to be on education, especially at school-age.
GUN CRIME: YEAR TO JUNE 04
Fatalities: 70 (-15%)
Serious injuries: 430 (no change)
Total firearms offences: 10,590 (+3%)
With replica/ imitation gun: 1,350 (+35%)
With handgun: 4,910 (-10%)
Source: Home Office recorded crime figures. Comparisons are with year to June 03
The police, he said, are limited in what they can do alone.
"People in communities are the ones who have the big say," he told me. "They can make the police aware there are drugs being sold. They'll never stamp it all out. But it's about reduction."
Back on the streets of St Paul's, the Reverend Palmer agreed the police needed support.
"I wouldn't say they're getting it completely right," she said, "but they're listening more. You can't just leave everything to the police. It's not just about locking people up, it's about working with youth."
We watched as she approached a group of teenage girls, hanging out together on a corner.
"Anyone need a prayer for anything?" bellowed the Reverend Palmer. Silence. "Anyone got exams coming up?"
The girls shuffled and stared at their feet.
"No, thanks, we're fine."
They were briefly blessed anyway and the Prayer Patrol moved on. What did they make of it?
"They don't make any difference," said one girl with force.
Her friend shrugged. "But they're good people," she said.