I have no interest in belonging to any other. But we have no control over the fellowship of the Spirit, for it embraces all those in whom the Spirit dwells. And if it is God who calls people into that fellowship through the Gospel, it is only God that can exclude them. He controls the fellowship and not ourselves. Thank God for that.
None can open is an equally pungent truth.
Let's face it. If we use fellowship to refer to anything less than the one, holy, catholic, apostolic church throughout the world, we are using it in a sectarian sense.