1 Corinthians 2:14-16
14: But the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know them, because they are spiritually discerned.
15: But he that is spiritual judgeth (examines & investigates) all things, yet he himself is judged of no (natural) man.
16: For who hath known the mind of the Lord, that he may instruct him? But we have the mind of Christ.