This was a Wednesday night in a Baptist church about 20 years ago. I have no idea how long I talked or what I said. People were in tears and coming forward to speak to the pastor and to hug me. Even men had tears rolling down their face and told me how powerful my words were. I think these kinds of events are exceptional, too, and that everyone should be prepared when preaching or speaking.
Preparation can include being willing to lay the notes aside for a few minutes.
Traditionally, we have no sermons prepared in advance but simply wait for the spirit to work among us, speaking what it will through whom it will. The experience of speaking, or should I say being spoken through, and not knowing what words came out of one's mouth, is not uncommon among us. This puts the emphasis on the message as a gift from the Holy Spirit, not the product of the deliverer's own will. Can't the Spirit work during the week while preparing I am all in favor of the Spirit working, but I also believe that he is working during the week I am struggling to write that sermon. I think that while I struggle to get the right word, the right phrase, the right illustration, down on paper the Spirit is sitting on my shoulder watching me type.