“He that is spiritual judgeth [discerneth] all things, yet he himself is judged [discerned] of no man” (I Cor. 2:15).
The truly spiritual man is so far above the wisest sages of this world, yes, so far above the mass of Christians with whom he comes into contact, that he can understand them, but they can never quite understand him.
We should all long to be truly spiritual, but what is true spirituality?
In the Pauline Epistles the human race is divided, by the Spirit, into four classes: the natural man, the babe in Christ, the carnal Christian, and the spiritual Christian.
All four of these are referred to in one passage of Scripture (I Cor. 2:14–3:4) and it should be noted that they are classified according to their ability to appreciate and assimilate “the things of God” as revealed in His Word.
Through diligent, prayerful study of the Word, and with a sincere desire to obey it, the spiritual man has come to know God and the Lord Jesus Christ more and more intimately. Babes in Christ and carnal believers about him cannot “discern” him, simply because they have not come to know God as he. But he, having grown to spiritual maturity, quite understands them. He is among those of whom it is written:
“But strong meat [solid food] belongeth to them that are of full age, even those who by reason of use have their senses exercised to discern both good and evil” (Heb. 5:14). source