“Is it legitimate in any way to say that non-elect members of the visible church are not part of the Church? Sure. Scripture is full of this kind of thing—a true Jew is one who is one inwardly, synagogues of Satan, you are of your father the devil, and countless more. Our whole point is that baptized covenant members are Christians, members of the Church, connected to Christ, etc. in some important sense, not that they are participants in these things in every sense. So, is there a legitimate way to say that non-elect members of the covenant are not part of the Church? Absolutely.”
The Auburn Avenue Chronicles Vol. 2, p. 714