The doctrine of separation, also known as the doctrine of non-fellowship, is a belief among some Protestant religious groups, such as the Exclusive Brethren, Independent Fundamental Baptists, and Bible Baptist churches, that the members of a church should be separate from "the world" and not have association with those who are "of the world".
Multiple texts in both the Old Testament and New Testament of the Bible provide the basis for this doctrine. For example, in the KJV translation :
Different groups vary widely in what to them constitutes separation. Additionally, there is a distinction between first and second degree separation. For example, many Christians want to live in a way that is distinct from the typical lifestyle of the world (first degree). This was supported by Dennis Costella when he said, "We are in the world, but we are not to be a part of it."[1] Exclusive Brethren are an Evangelical Protestant group who hold strongly to the doctrine of separation, as they isolate themselves from those not of their community.[2] A similar but less extreme form is the position held by Independent Fundamental Baptists and Bible Baptist churches.[3] Others would claim that not only should one separate from the world, but also from those Christians who would not separate themselves from the world (second degree). Believers in second degree separation believe that Christians who are tied up with "the world" are themselves guilty of apostasy for their failure to adequately separate.
Practices and areas that should be separated under the more strict interpretations of the doctrine of separation include:
The doctrine of separation often leads to ecclesiastical separatism, in which Christians leave Christian denominations that they believe are apostate, in accordance with Revelation 18:4.