There have been a few recent discussions about whether or not biblical separation is for the purity of the gospel or the purity of the church. Some profess confusion over why others say separation is over the purity of the gospel before it is for the purity of the church.
The reason is actually pretty simple, I think.
Of course, I actually thought about it, which puts me in a small minority of people, particularly of those who blog. But I digress …
The reason is that the gospel, not the church, is the boundary of Christian fellowship. There can be no Christian fellowship with those who are outside the bounds of the gospel. This is a matter of definition. To be a Christian means to be inside the bounds of the gospel.
The church, speaking of the visible church (whether a particular local assembly or those who profess faith in Christ but are not a part of our local assembly), might contain those outside the boundary of the gospel. With these, we have a false fellowship, which is purely surface and indeed is no fellowship at all.
For me, this does not minimize the church. It simply recognizes that a pure church stands on the shoulders of a pure gospel. It is the gospel that marks the boundaries of Christian fellowship. A church will usually have some false professors in it.
The gospel is prior to the church. The gospel creates the church, and establishes the boundary for the church.
The gospel sets the basis for the purity of the church which we guard by guarding the purity of the gospel.