True wisdom is the result of human reason coupled with revelation. Yet, even true wisdom will result only if a person believes what God says. Only then does a person have the opportunity to see God. He is hidden from those who put their faith in human wisdom.
Natural in this context does not mean "evil." It simply refers to one whose horizons are bounded by the things of natural life, by "the around and the about." Such a person is not equipped to discern the activities of God. But a person with the Holy Spirit can examine God's activities and make judgments based on them. Therefore, in his process of judgment, God comes into the picture. When the Spirit of God comes into a person's life, the basis of his judgment should change! This occurs, not because the person is any "greater" or "better," but because the Spirit of God equips him to see and to use godly wisdom. Now he can judge all things from God's perspective. This indeed is our responsibility!
Because God has called us, we should see God so clearly and know His greatness so intimately that we can live in the expectation that something great can happen at any moment to those who are receptive. The God who raised up Jesus is equal to any occasion—any possibility! Is anything too hard for Him? Certainly not! He throws that challenge out to man—to those who truly see Him.