In Romans 16:17, Paul writes the following: I appeal to you, brothers, to watch out for those who cause divisions and create obstacles contrary to the doctrine that you have been taught; avoid them. Notice what Paul says here. Contrary to the modern notion that doctrine divides, Paul here says the exact opposite: these people who must be avoided are divisive precisely because they have departed from the true teaching. It is their doctrinal deviance, their departure from true teaching, that makes them sources of division. If Romans 10:9-10 made the positive case for doctrine as a vital part of belonging, here Paul states the other side of the case, that wandering away from sound doctrine means being divisive and ceasing to belong. The Creedal Imperative , Carl R. Trueman, Crossway 2012, pg. 68.