In context it refers to the deeper hidden things in the mind of GodThe unregenerate with the heart of nature cannot understand Spiritual Truth 1 Cor 2:14
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.
But the natural [unbelieving] man does not accept the things [the teachings and revelations] of the Spirit of God, for they are foolishness [absurd and illogical] to him; and he is incapable of understanding them, because they are spiritually discerned and appreciated, [and he is unqualified to judge spiritual matters].AMP
1 Corinthians 2:10–13 (KJV 1900) — 10 But God hath revealed them unto us by his Spirit: for the Spirit searcheth all things, yea, the deep things of God. 11 For what man knoweth the things of a man, save the spirit of man which is in him? even so the things of God knoweth no man, but the Spirit of God. 12 Now we have received, not the spirit of the world, but the spirit which is of God; that we might know the things that are freely given to us of God. 13 Which things also we speak, not in the words which man’s wisdom teacheth, but which the Holy Ghost teacheth; comparing spiritual things with spiritual.
It does not reference the revealed gospel