sin: the enemy of usefulness

Sin "will take away a man’s usefulness in his generation. His works, his endeavours, his labours, seldom receive blessing from God. If he be a preacher, God commonly blows upon his ministry, that he shall labour in the fire, and not be honoured with any success or doing any work for God; and the like may be spoken of other conditions. The world is at this day full of poor withering professors. How few are there that walk in any beauty or glory! how barren, how useless are they, for the most part! Amongst the many reasons that may be assigned of this sad estate, it may justly be feared that this is none of the least effectual, — many men harbour spirit-devouring lusts in their bosoms, that lie as worms at the root of their obedience, and corrode and weaken it day by day. All graces, all the ways and means whereby any graces may be exercised and improved, are prejudiced by this means; and as to any success, God blasts such men’s undertakings...Keep alive upon thy heart these or the like considerations of its guilt, danger, and evil; be much in the meditation of these things; cause thy heart to dwell and abide upon them; engage thy thoughts into these considerations; let them not go off nor wander from them until they begin to have a powerful influence upon thy soul, — until they make it to tremble."
John Owen, Chapter 10, Mortification of Sin