|Cyprian of Carthage|
In our time though almost any belief or teaching can be called -- and is called -- "christian" by those inclined to do so.This isn't a new phenomenon, though. Cyprian of Carthage grumbled about it just 200 years after Jesus' time, pointing out that it's rather important to get it right.
How can a man say that he believes in Christ, who does not do what Christ commanded him to do? Or whence shall he attain to the reward of faith, who will not keep the faith of the commandment? He must of necessity waver and wander, and, caught away by a spirit of error, like dust which is shaken by the wind, be blown about; and he will make no advance in his walk towards salvation, because he does not keep the truth of the way of salvation.
Cyprian of Carthage (200 - 258)
“On the Unity of the Church,”