Verbal communication involves three things:
1. What you say.
2. How you say it.
3. Belief in the person giving the message.
Let's call these steps:
TRUTH.
PASSION.
INTEGRITY.
The ancient Greeks also had words for these steps. They are:
Logos.
Pathos.
Ethos.
Great preaching begins with logos, with good content. Logos is brainy. It's logical. It's lectures and homework and quizzes and exams.
Pathos builds on logos. It's personal more than logical. It's passion, enthusiasm, application. You want your audience not only to know something but to act upon it.
Ethos is all about your credibility as a speaker, which is determined by 2 things: your knowledge, and your experience in the subject at hand. You really know your stuff. What's more, you've lived it. Ultimately, ethos comes down to trust. How can I gain my audience's trust so that they will accept the truth of God's word?
Did you know that there's a verse in the New Testament that talks about all three of these things? It's 1 Thess. 1:5. Here's how the NLT puts it: "For when we brought you the Good News, it was not only with words (logos) but also with power (pathos), for the Holy Spirit gave you full assurance that what we said was true. And you know of our concern for you from the way we lived when we were with you (ethos)."
There you have it. The Triple Crown of Preaching!
P.S. Paul lived in Thessalonica for about 5 weeks. While there, the Thessalonians got to know him. Paul gave them the gospel, yes, but it wasn't just a pack of words. In 1 Thess. 2:8 Paul says he "gave them his own life." He was real. He was for them. He wasn't in it for the money. They saw his strengths, but they also saw the cracks in his life. This is the kind of guy I can identify with, they must have said. He had a true walk with God. Wasn't perfect. But it was authentic.
Don't be afraid to be transparent, preacher!