Martin Luther put it, ‘The sure mark by which the Christian congregation can be recognized is that the pure gospel is preached there. For just as the banner of an army is the sure sign by which one can know what kind of lord and army has taken to the field, so to the gospel is the sure sign by which one can knows where Christ and his army are encamped…. likewise, where the gospel is absent and human teachings rule, there no Christians live but only pagans, no matter how numerous they are.”