Not content with fire and brimstone, this no-nonsense mix of Rambo and the Archbishop of Canterbury also favours the Kalashnikov AK-47 among the weaponry in the Lord's arsenal.
He's Sam Childers (Butler), a onetime jailbird, drug addict and minor criminal whose conversion to Christianity (at the behest of his ex-stripper wife [Monaghan]) has resulted in him renouncing his sin-laden old ways.
Inspired by a visit to his church from an American missionary in Africa, Childers takes his practical skills as a builder to a small village on the Ugandan/Sudan border.
It is there that he learns about the barbaric Lord's Resistance Army, a terrorist renegade militia that specialises in coercing press-ganged youngsters into murdering their parents. His path is set when he witnesses a young boy blown apart by a landmine as he runs through a field.
What was once a charitable Christian mission now turns into a crusade with Childers putting his evangelical fervour into building an orphanage and his practical zeal into the armed and violent rescue of youngsters captured by the LRA.
Director Marc Forster - in his first offering since Quantum of Solace - opts for a straightforward retelling of Childers' story without much time for those that question his gung-ho claims or voice concern at his eye-for-an-eye-style methods.
Butler's bullet-headed acting style suits the role and convincingly charts the old biking bruiser's course from heroin-injecting no-hoper to rebel with a Christian cause.
However, there is an unease that important issues are being ducked and Forster's solid treatment of his subject leaves little room for a considered response to a controversial story.
This machine gun preacher offers lots of noise but casts little light.