The task of true biblical preaching is not essentially intellectual or psychological or rhetorical; it is essentially spiritual. I have followed the preaching ministry of more men than I can count and have discovered that many fall into a great trap. I was truly blessed to discover that my concerns are shared with many others and have been so wonderfully articulated in this excerpt from "What is Biblical Preaching" by Eric J. Alexander, P&R, 2008:
"Left to ourselves, we may do many things with a congregation. We may move them emotionally. We may attract them to ourselves personally, producing great loyalty. We may persuade them intellectually. We may educate them in a broad spectrum of Christian truth. But the one thing we can never do, left to ourselves, is to regenerate them spiritually and change them into the image of Jesus Christ, to bear his moral glory in their character. While that is the great calling of the church of Christ, it is essentially God’s work and not ours.
So it is possible to be homiletically brilliant, verbally fluent, theologically profound, biblically accurate and orthodox, and spiritually useless. That frightens me. I hope it frightens you, too. I think it is of this that Paul is speaking when he says, “I planted the seed, Apollos watered it, but God made it grow. So neither he who plants nor he who waters is anything, but only God, who makes things grow” (I Cor. 3:6-7). It is very possible for us to be deeply concerned about homiletical ability and fluency and theological profundity and biblical orthodoxy, but to know nothing of the life – giving power of God with the burning anointing of the Holy Spirit upon our ministry. Campbell Morgan (Lloyd-Jones’s predecessor at the Westminster Chapel) divulged that at one crucial stage in his ministry he was in precisely this position, and sensed that God was saying to him, “Preach on, great preacher, without me.” Alan Redpath used to say that the most penetrating question you could ask about any church situation was, “What is happening in this place that cannot be explained in merely human terms?”
So there is a world of difference between true biblical preaching and an academic lecture or a rhetorical performance. We are utterly dependent on the grace and power of the Holy Spirit. Thank God, he uses the weak things of this world to confound the mighty, and the things that are not to bring to nothing the things that are (1 Cor. 1 :2,8). This is why it is absolutely essential to marry prayer to the ministry of the Word. In our ministries prayer is not supplemental; it is fundamental. Of course we subscribe to the principal that “this work is God’s work, not ours.” We subscribe to that because we are biblical Evangelicals, but the logical corollary of that statement is that prayer is a fundamental issue in the ministry of the Word, as in every part of our labor, and not, as we tend to make it, a supplemental matter."