Snitched on: His robbery crew. After successfully pulling off the robbery of an armored car, false-preaching Cleon (Bokeem Woodbine) opts not to lay low, instead buying a new Cadillac and handing out 100 dollar bills to his congregation, claiming he got it from the Lord. The police eventually catch up to his bullshit and he rats out the surviving members of his crew.
Punishment for snitching: We never find out, but we're sure there's a circle of hell reserved for he who rats out his boys.