False Unity is man-centered.
If you go back through the long history of the Church, you will find that it has often counted most, and has been most used by God, when there have been just a handful of people who were agreed in spirit and in doctrine. God took hold of them and used them and did mighty things through them. But when there was only one Church in the whole of western Europe, what did she lead to? The Dark Ages.
And yet it seems to me that this great lesson of history is being entirely forgotten and ignored at this present time. I say these things not because I am animated by any controversial spirit, but because I have a zeal for the truth as I find it in the Scriptures, and regard it as tragic to note the way in which Scripture is being twisted and perverted in the interests of a unity which is not a unity.
~ Martyn Lloyd-Jones
Great Doctrines of the Bible: The Church.