Hear is the secret to that. I listened to a collection of over 500 one hour Bible Sermons by Dr. John MacArthur and Dr. Chuck Swindoll, over almost a decade, and at least 4 times each on those tapes. At work, while I sorted mail. That was before I moved to California. Even Dr. MacArthur said in a sermon, "I never really understood what FILLED WITH THE SPIRIT meant, until one Sunday I stepped into the Pulpit, opened my Bible, and my Sermon notes were GONE! I had to DEPEND on the HOLY SPIRIT to Give me what HE wanted to say. That is definitely want FILLED with the Spirit meant at that moment." I took that message and went a step further than John did. That First Sermon of mine was Totally Dependent on the HOLY SPIRIT. So like my Grandfather taught me, "I it works, DON'T FIX IT." I just applied that to my sermon notes. So my sermon notes was a dozen or more of Verses, with a nice border, and a couple of appropriate Pen and Ink Pictures. Mostly because inmates usually do not know enough to find the Books of the Bible quickly, so it was for their convenience to follow alone easily. BUT as I stepped into the Pulpit I always opened with a Dr. Ed Young Prayer.
"Lord, I thank you for your Holy Word, that You gave threw the Prophets of Old, and threw the Apostle. Father, let me get out of the way, and You speak, that this message will be as pure and true as you originally gave it. In Jesus Name I pray."
I meant that PRAYER with all my heart and being, and then proceeded to TRUST HIM TOTALLY to give me the Words HE wanted me to speak, on the verses I had prepared. I also let HIM pick the SUBJECT each week. I Trust that He would bring an event, IN MY PATH, that would trigger my Mind, "THAT IS WHAT THE LORD WANTS ME TO TEACH THIS WEEK. Like I said, "IF IT WORKS, DON'T FIX IT." Yes some of it came from Dr. MacArthur or Dr. Swindoll sermons, but a lot of it was insight that the Holy Spirit brought into my mind. BUT IT JUST FLOWED. There was NO STAMMERING OR SHUDDERING. Some how I believe that is HOW the Apostles prepared their sermons,
JUST TRUSTING THE LORD.
I Taught sermons like that for almost 12 years, and never wrote out a single SERMON. I just pulled together verses on a specific subject, and printed them for the inmates.