"But the 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."
(1 Corinthians 2:14)
It is sometimes frustrating that seemingly intelligent people are so ignorant and unresponsive when presented biblical truth and wisdom. We are reminded that the natural man (unbeliever) has neither the desire, nor the ability to understand biblical truth and wisdom. It is not a matter of intelligence or education. The unbeliever does not have the Holy Spirit who alone provides spiritually understanding of God's truth.
When someone hears and believes the gospel of the Lord Jesus Christ, many wonderful things happen. The Holy Spirit immediately takes up residence in the life of the new believer; "However, you are not in the flesh but in the Spirit, if indeed the Spirit of God dwells in you. But if anyone does not have the Spirit of Christ, he does not belong to Him." (Romans 8:9). Believers who have the Holy Spirit now have the spiritual ears and eyes to hear and see those things that are spiritually appraised.
While it is frustrating when people just don't understand or believe what to us is so obvious, we should remember that old saying; "don't try to teach a pig to sing. It will only frustrate you and irritate the pig!" Jesus said it this way; "Do not give what is holy to dogs, and do not throw your pearls before swine, or they will trample them under their feet, and turn and tear you to pieces." (Matthew 7:6)
It is a waste of time trying to get unbelievers to understand biblical truth and wisdom. They can't understand, nor do they have the power to trust and obey God's word no matter how effectively it is preached. What every unbeliever first needs to hear and believe is the gospel. It is our responsibility to share this basic biblical truth with them and to pray that God, in His marvelous grace and mercy, will give them the faith to hear and believe and receive the Spirit of Christ; "But if the Spirit of Him who raised Jesus from the dead dwells in you, He who raised Christ Jesus from the dead will also give life to your mortal bodies through His Spirit who dwells in you. (Romans 8:11)
Don't get frustrated! We too were once spiritually blind. But praise God that He has opened our eyes and now we see. Maranatha!