But a natural man does not accept the things of the Spirit of God, for they are foolishness to him; and he cannot understand them, because they are spiritually appraised. But he who is spiritual appraises all things, yet he himself is appraised by no one. For who has known the mind of the Lord, that he will instruct him? But we have the mind of Christ.
Paul refers to the “natural man” in contrast with “he who is spiritual,” or to put it another way, the “spiritual man.” Christians like to add a third category, the “carnal Christian,” but Paul does not allow this. You are either a Christian and therefore a spiritual person, or you not a Christian and therefore a natural person.
The word “natural” (Greek “psuchikos”) means “behavior which is typical of human nature” (BADB). The natural man is he who lives his life without any reference to spiritual truth. He could have common sense, academic acumen, or business success. But without the Spirit of God he is without divine input, insight, or wisdom. He may ply his way through the world well enough, but there is no connection with God in any meaningful sense.
The spiritual man is he whose life has been infused by the Spirit of God. In addition to and superseding the knowledge of the world that the natural man has, believers have a spiritual awareness that affects how they view everything. Their spiritual conscience has been raised from the dead. The natural man cannot understand this and may even see Christians as weird for what they believe. But it is not the appraisal of the natural man that should concern us. We who believe should be more concerned about the evaluation of our life, our life-style and our worldview that is based on a spiritual appraisal.
In Paul’s teaching, there is the category of natural man (non-believers) and the category of spiritual man (believers). Both are legitimate ways of viewing people. But the category of “carnal Christian” is not legitimate! For even the Corinthians who were living carnally are spiritual, for they are included when Paul writes, “But we have the mind of Christ.” To be sure, the Corinthians were carnal, and at times, in the worst possible way. But they had become callous to the Spirit and forgotten about Christ and Him crucified; they had settled for what to them was “normal” Christianity—and they were quite comfortable in it, despite the conflict and divisions in the church! Paul’s point is that such Christian behavior is an illegitimate way of life. So he calls on the Corinthians to think of themselves and to live up to the standard of “saints by calling, with all who in every place call on the name of our Lord Jesus Christ…” (1 Cor. 1:2), and reminds them that they do have the mind of Christ.
Lord, help me to rise to the truth that I am spiritual with the mind of Christ.

I was struggling, as a christian to understand the Bible talking about the mind, heart and Soul, and thought that those confusing words does not matter,but fail to understand everytime, especially Paul talking about.
I was forced to read it again and again, at least to seems to understand. But this clarity really opened my understanding even of the old testament. Now the Bible is alive in me.