I love the goal that drives Paul's preaching method in 1 Cor. 2:5 -- So that your faith might not be in the wisdom of man but in the power of God. He made deliberate choices to insure their faith had a sure foundation.
After rehearsing the logic and the necessity of the Spirit, the writer, wanting to insure our dependence on the Spirit says, "The natural man doesn't receive the things of the Spirit of God; they are foolishness to him and he is not able to know them." We must develop a Spirit-dependence in evangelism. Well, this chapter would say we need Spirit-dependence in everything.