And I, when I came to you, brothers, did not come proclaiming to you the testimony of God with lofty speech or wisdom. For I decided to know nothing among you except Jesus Christ and him crucified. And I was with you in weakness and in fear and much trembling, and my speech and my message were not in plausible words of wisdom, but in demonstration of the Spirit and of power, so that your faith might not rest in the wisdom of men but in the power of God.

1 Corinthians 2:1-5, ESV