1 Corinthians 2:4-7

And my message and my preaching were very plain. Rather than using clever and persuasive speeches, I relied only on the power of the Holy Spirit. I did this so you would trust not in human wisdom but in the power of God. Yet when I am among mature believers, I do speak with words of wisdom, but not the kind of wisdom that belongs to this world or to the rulers of this world, who are soon forgotten. No, the wisdom we speak of is the mystery of God—his plan that was previously hidden, even though he made it for our ultimate glory before the world began.