“True Christianity” is a centered set and not a bounded set. Neither I nor any other mere human has the authority to decide who is and who is not a true Christian—other than as a matter of personal opinion. There are times, however, when churches (denominations) find it necessary to decide who is not a true Christian
Several times recently I’ve mentioned “real Christians” here. A few visitors and commenters have objected to the concept. How is it possible to discriminate between “real Christians” and, well, false Christians?
If we start at the other end, so to speak, and talk about “false Christians,” it’s easier to understand why it’s necessary to speak about real Christians. Who can doubt there have been and are false Christians?
I confess that this habit of distinguishing between true and false Christians is something I grew up with and it was often abused by the Pentecostals and conservative evangelicals that surrounded me in my family, church and wider religious community.
But just because a concept or category is abused doesn’t mean it isn’t valuable or necessary. Somewhere I heard that “the cure for abuse isn’t disuse but proper use” (referring to good or necessary ideas, terms, categories).
The distinction between real Christians and false Christians is rooted in the New Testament itself. 1 John 2:19 speaks of “antichrists” who went out from the church but never belonged to it in the first place. Obviously, the writer is speaking of people who pretended to be Christians, may have even thought they were Christians, were among the people of God, but were not true Christians.
Luther talked much about the “false brethren.” I may not agree that the people he so identified were truly false, but I agree with the category. I would just populate it differently (in some cases).
Kierkegaard staked much on the distinction between true and false Christians. He wrote that in a country (such as his) where everyone is a “Christian” by birth, true Christianity does not exist.
Who can seriously say there are no false brethren today? It may sound ungenerous to talk about true versus false Christians, but just to mention white supremacy churches is to make the distinction unavoidable.
Anyone who has lived in a culture where everyone thinks they are Christians simply because they were baptized at birth or walked the aisle at some time (to join a church) is to know the reality of false Christianity.
Another term for false Christianity is “nominal Christianity”—Christianity in name only.