Perhaps the greatest beneficiary of the sermon is the preacher himself, for only the message which is first of all addressed and applied to me will carry any real authenticity when preached to others. In order for this to happen, both preacher and hearers need the illumination and help of the Holy Spirit. Without that divine empowering, the most thorough of preparation and most professional of presentation will prove to be mere words. With the Holy Spirit's help, the words of the poorest of preachers can become the very words of God.
Excerpted from Firm Foundations: Over 200 examples of how to structure a sermon by Peter Grainger (Christian Focus, 2011). A PDF sample of the table of contents and the introduction are available here: LINK.