From ‘Whole Bible Christianity’ chapter 4 ‘The Natural Man and Spiritual Relevance’
For who knows a person’s thoughts except the spirit of that person, which is in him? So also no one comprehends the thoughts of God except the Spirit of God. Now we have received not the spirit of the world, but the Spirit who is from God, that we might understand the things freely given us by God. And we impart this in words not taught by human wisdom but taught by the Spirit, interpreting spiritual truths to those who are spiritual. The natural person does not accept the things of the Spirit of God, for they are folly to him, and he is not able to understand them because they are spiritually discerned. The spiritual person judges all things, but is himself to be judged by no one. “For who has understood the mind of the Lord so as to instruct him?” But we have the mind of Christ. (1 Corinthians 2:11–16, ESV)
The “natural person” does not accept the things of the Spirit of God, for they are folly to him. The Word (the Law) looks foolish, so he refuses to do anything God says. God’s Law is spiritual (Romans 7:14) so a natural man does not think it is relevant. It is as if a starving man were at a banquet but refusing to eat because it isn’t served on china. All he has to do is reach out his hand and partake of God’s blessings, but he won’t because it is served on wood plates. Only when we humbly submit to God do we see that His knowledge is not foolish. When we reject the knowledge of God given in the Law, it shows that we are not spiritual. A new heart of flesh written with the Law by the Spirit recognizes the blessings in the Law freely given us by God.