One of the questions that inevitably comes up when you study church history, especially the history of the Reformation, is whether the Roman Catholic Church should be considered Christian. On the one hand, they affirm the Nicene Creed which places them within the pale of historic Christianity along with Protestants and the Eastern Orthodox. On the other hand, they reject the notion of salvation by grace through faith alone. This puts them in the position of preaching a gospel other than the one affirmed by the apostles which, in turn, puts them under condemnation according to the Apostle Paul (Galatians 1:8-9).
So what are we to think about the Roman Catholic Church? Are they Christian because they are within the pale of Nicene orthodoxy or are they not Christian because they preach a false gospel? Additionally, how do we understand the difference between Nicene Roman Catholicism and something like Mormonism?
The answer lies in understanding the purpose of the creeds. The Nicene Creed in particular was not intended to be an exhaustive theological statement. It was formulated to address particular issues the church was facing at the time it was written – primarily the challenge to the divinity of Christ being put forth by the Arians. The Creed says nothing about the nature of the atonement, justification, etc. But, it does put up some boundaries beyond which a belief system cannot be Christian. So, from a historical and sociological perspective, religions within Nicene boundaries are considered Christian. But, this does not mean everyone who affirms Nicaea can be considered Christian from a theological perspective, as it is merely a starting point.
One way I’ve sorted this out is thinking of an apple pie. There are certain ingredients that must be present for a pie to be considered an apple pie. For argument’s sake, let’s say those ingredients are apples, sugar and nutmeg. Pies that contain apples, sugar and nutmeg can be classified as Apple Pies:
Of course, we can add other things to the pie like rhubarb, for example, and it would still be an apple pie. But, are there things we can add that are so contrary to the pie’s purpose that, while technically still an apple pie, it becomes worthless as such? I think so:
A pie containing apples, sugar, nutmeg, sardines and garlic may be in the apple pie category technically but will not function as an apple pie in any meaningful sense.
Roman Catholicism is like an apple pie with sardines and garlic added – technically in the category of Christian but containing so many extra ingredients that are in conflict with the basics that it ceases to be Christian in reality.
For Mormonism and other anti-Nicene cults who call themselves Christian, the apple pie looks like this:
They use peaches but call it an apple pie even though it is nothing of the kind and never has been. Mormonism began, not with Nicene orthodoxy from which they’ve strayed, but with heresy in which they’ve continued. They’re a peach pie masquerading as apple.
So while the Nicene Creed addresses essential beliefs it is not an exhaustive list of those essentials. The crux of Christianity is the gospel. If I affirm the divinity of Christ and the reality of the Trinity in sync with Nicaea but deny that the work of Christ alone is sufficient for my salvation, I have denied the gospel and forfeited the right to call myself a Christian. That is why, though we don’t place Roman Catholicism in the category of a cult like Mormonism, we must still place it outside the faith once for all delivered to the saints (Jude 1:3).