It now becomes a serious question how far those who abide by the faith once delivered to the saints should fraternize with those who have turned aside to another gospel. Christian love has its claims, and divisions are to be shunned as grievous evils, but how far are we justified in being in confederacy with those who are departing from the truth? It is a difficult question to answer so as to keep the balance of the duties. For the present it behooves believers to be cautious, lest they lend their support and countenance to the betrayers of the Lord.     

   It is one thing to overleap all boundaries of denominational restriction for the truth’s sake; this we hope all godly men will do more and more. It is quite another policy which would urge us to subordinate the maintenance of truth to denominational prosperity and unity. Numbers of easy-minded people wink at error as long as it is committed by a clever man and a good-natured brother, who has so many fine points about him. 

   Let each believer judge for himself; but, for our part, we have put on a few fresh bolts to our door, and we have given orders to keep the chain up; for under color of begging the friendship of the servant, there are those about who aim at robbing THE MASTER. 

Spurgeon: A Biography - Arnold Dallimore