Gal 5:16 This I say then, Walk in the Spirit, and ye shall not fulfil the lust of the flesh.
Gal 5:17 For the flesh lusteth against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that ye cannot do the things that ye would.
1Co 3:18 Let no man deceive himself. If any man among you seemeth to be wise in this world, let him become a fool, that he may be wise.
1Co 3:19 For the wisdom of this world is foolishness with God. For it is written, He taketh the wise in their own craftiness.
1Co 3:20 And again, The Lord knoweth the thoughts of the wise, that they are vain.
1Co 2:14 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.
The flesh will want to rebel against the truth all in an attempt to exalt themselves so they will reject the cross, and they cannot understand how a man can shed his blood to take away our sins because of their exaltation of themselves, and have a different viewpoint of reality and what prospers them.
2Ti 4:2 Preach the word; be instant in season, out of season; reprove, rebuke, exhort with all longsuffering and doctrine.
2Ti 4:3 For the time will come when they will not endure sound doctrine; but after their own lusts shall they heap to themselves teachers, having itching ears;
2Ti 4:4 And they shall turn away their ears from the truth, and shall be turned unto fables.
The time will come that they will not want to hear about the cross, and Jesus is Lord and Savor, but believe he evolved to be spiritual the same as they want to do.
The world will exalt themselves so they do not want to accept that someone can save them that is a human being like them, and do not understand the shedding of blood to take away sins, and that they need their sins taken away to be saved.
Rom 1:17 For therein is the righteousness of God revealed from faith to faith: as it is written, The just shall live by faith.
Rom 1:18 For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness;
Rom 1:19 Because that which may be known of God is manifest in them; for God hath shewed it unto them.
Rom 1:20 For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse:
Rom 1:21 Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened.
Rom 1:22 Professing themselves to be wise, they became fools.
Joh 20:27 Then saith he to Thomas, Reach hither thy finger, and behold my hands; and reach hither thy hand, and thrust it into my side: and be not faithless, but believing.
Joh 20:28 And Thomas answered and said unto him, My Lord and my God.
Joh 20:29 Jesus saith unto him, Thomas, because thou hast seen me, thou hast believed: blessed are they that have not seen, and yet have believed.
Also the world does not have faith for they want to have visible proof of something to believe it such as the atheists which they say prove God exists.
The flesh will reject the truth of the cross for whatever reason.
And even we would of never came to the truth by the flesh alone for it took God to intervene in our life before we were saved to be saved.
Which no person says that Jesus is the Lord, but by the Holy Ghost.
And no person comes to the Son unless the Father draws them.
And Peter said Jesus is the Christ, the Son of the living God, and Jesus said flesh and blood did not reveal that to him but the Father.
And those that believe Jesus is come in the flesh is of God.
So if you confess these things then God has to be working in your life.
It is the foolishness of preaching because the world thinks it is foolishness, and it is the preaching of the cross that is foolishness to them, and look at how many people reject the cross such as Buddhists, Hindu, Islam, other religions as they look at prosperity and God from a natural perspective as well as spiritual, and many reject the cross.
Many people do not get the cross and understand it whether from exaltation of themselves, say they do not have proof, or believe another reality for their prosperity and spirituality, or grew up with a belief in their nation other than Christianity and think it is reality.