Departure from the faith is of two aspects; doctrine and praxis (life). It can be one or the other or in many cases both, for wrong doctrine leads to wrong living. But not all false professors are identifiable for their counterfeit profession is just that... counterfeit. Like a counterfeit $20 bill, it looks nearly identical to the real thing and it is often very difficult to see the difference. This is one of the most pressing responsibilities of the Elders of the Church; to examine those seeking membership to determine whether or not one's profession is credible according to the teaching of Scripture.