From E.M. Bounds we read,
The sweetest graces by a slight perversion may bear the bitterest fruit. The sun gives life, but sunstrokes are death. Preaching is to give life; it may kill. The preacher holds the keys; he may lock as well as unlock. Preaching is God’s great institution for the planting and maturing of spiritual life. When properly executed, its benefits are untold; when wrongly executed, no evil can exceed its damaging results. It is an easy matter to destroy the flock if the shepherd be unwary or the pasture be destroyed, easy to capture the citadel if the watchmen be asleep or the food and water be poisoned. Invested with such gracious prerogatives, exposed to so great evils, involving so many grave responsibilities, it would be a parody on the shrewdness of the devil and a libel on his character and reputation if he did not bring his master influences to adulterate the preacher and the preaching. In face of all this, the exclamatory interrogatory of Paul, “Who is sufficient for these things?” is never out of order.
Paul says: “Our sufficiency is of God, who also hath made us able ministers of the new testament; not of the letter, but of the spirit: for the letter killeth, but the spirit giveth life.” The true ministry is God–touched, God–enabled, and God–made. The Spirit of God is on the preacher in anointing power, the fruit of the Spirit is in his heart, the Spirit of God has vitalized the man and the word; his preaching gives life, gives life as the spring gives life; gives life as the resurrection gives life; gives ardent life as the summer gives ardent life; gives fruitful life as the autumn gives fruitful life. The life–giving preacher is a man of God, whose heart is ever athirst for God, whose soul is ever following hard after God, whose eye is single to God, and in whom by the power of God’s Spirit the flesh and the world have been crucified and his ministry is like the generous flood of a life–giving river. (Taken from the Power of Prayer by E.M. Bounds)