We've been considering the issue of fellowship and separation in some of my recent posts. This last Sunday evening in our church, I preached just a basic sermon on this issue, entitled "The Basis of our Fellowship with Others." I recognize that in the sermon, some who read here will find some disagreement, as I briefly mention the preservation of Scripture issue and the local church issue. Besides that, this will give you a very basic understanding of the doctrine of separation in Scripture as we consider what is the basis of our fellowship.
The Basis of Our Fellowship with Others
Click on the above link to either listen online or to download this sermon. It is about 40 minutes long. It doesn't cover everything on the issue, but it should help someone to get a taste of the doctrine.