1 Corinthians 2:3-5

I came to you in [a state of] weakness and fear and great trembling. And my message and my preaching were not in persuasive words of wisdom [using clever rhetoric], but [they were delivered] in demonstration of the [Holy] Spirit [operating through me] and of [His] power [stirring the minds of the listeners and persuading them], so that your faith would not rest on the wisdom and rhetoric of men, but on the power of God.