Controversy and conflict in the church are never to be relished or engaged in without sufficient cause. But in every generation, the battle for the truth has proved ultimately unavoidable, because the enemies of truth are relentless. Truth is always under assault. And it is actually a sin not to fight when vital truths are under attack. That is true even though fighting sometimes results in conflict within the visible community of professing Christians. In fact, whenever the enemies of gospel truth succeed in infiltrating the church, faithful believers are obliged to take the battle to them even there. That is certainly the case today, as it has been since apostolic times.

– John MacArthur