This section is showing that Paul subordinated himself to the glory and the power of the message! His power was not in pretentious and clever rhetoric. Please understand that. When I am talking about "persuasive arguments," I am not talking about carnal rhetoric. We might be talking about just plain down-to-earth words, but they are in harmony with the scriptures of God.
That is where the power is—combined with the Spirit of God! Remember that Jesus said: "The words that I speak unto you, they are spirit and they are life."
Paul subordinated himself to the glory and the power of the message. And so, the message that he gave contains simple words; but, combined with the Scripture and the Spirit of God working with those whom God was calling, they had powerful impact on them. That is what this chapter is about.