http://www.spurgeon.org/misc/sw08.htm
Brethren, we have been greatly disappointed, have we not, with some of our converts? We shall always be disappointed with them so far as they are our converts. We shall greatly rejoice over them when they prove to be the Lord's work. When the power of grace works in them, ("Glory!") then it will be, as my brother says, "Glory!" and nothing else but glory; for grace brings glory, but mere oratory will only create sham and shame in the long run. When we are preaching, and we think of a very pretty, flowery passage, a very neat, poetical paragraph, I wish we could be restrained by that fear which acted upon Paul when he said that he would not use the wisdom of words, "lest the cross of Christ should be made of none effect."
Believe in preaching the love of Christ, believe in preaching the atoning sacrifice, believe in preaching the new birth, believe in preaching the whole counsel of God. The old hammer of the gospel will still break the rock in pieces; the ancient fire of Pentecost will still burn among the multitude. Try nothing new, but go on with preaching, and if we all preach with the Holy Ghost sent down from heaven, the results of preaching will astound us.