[Preaching] cannot be taught. That is impossible. Preachers are born, not made. This is an absolute. You will never teach a man to be a preacher if he is not already one. All your books such as The ABC of Preaching or Preaching Made easy should be thrown in to the fire as soon as possible. But if a man is a born preacher you can help him a little – but not much. He can perhaps be improved a little here and there.
How can that be done? Here I am probably going to be somewhat controversial. I would say: Not in a sermon class, not be having a student to preach a sermon to other students who then proceed to criticise matter and manner. I prohibit that. Why? Because the sermon in such circumstances is being preached with a wrong object in view; and the people who are listening to it are listening in a wrong way. The message of the Bible should never be listened to in that way. It is always the word of God, and no one should ever listen to it except in a spirit of reverence and godly expectation of receiving a message.
Martin Lloyd-Jones: Preaching and Preachers