Doctrine & Spiritual Health?

But Paul doesn't simply say that right doctrine is necessary; it's also "sound." The Greek word he uses here means healthy rather than diseased. This is Paul's way of saying wrong doctrine eats away at your spiritual health. Or, to put it another way, if you lack spiritual vitality and fruit, if you're not courageous enough, or joyful enough, or filled with love and hope, it may be because your grasp of biblical doctrine is shallow and thin, or distorted and mistaken. ~ Gospel Coalition

http://thegospelcoalition.org/blogs/tgc/2013/03/19/why-studying-doctrine-is-the-best-medicine/