Peter Kreeft writes about what it means to be a Christian:
"If 'to become a Christian' means to receive the real, objective Christ, then the only way to be saved is to become a Christian. But nothing in Scripture proves that Socrates was not a Christian in this sense. If on the other hand 'to become a Christian' means to knowingly profess the orthodox faith in Christ, then you do not need to be a Christian to be saved, or else Abraham is unsaved, and so are all who believe orthodox ideas. How unorthodox do your ideas have to be in order to send you to hell? Where is the dividing line? Does God give you a theology exam?"
via Jeremy Olson