Ok so the link is -
Natural person cannot understand God... The bible is the word of God ... Therefore the natural person cannot understand the bible?
Natural people can understand plenty from the Bible and it is good for them to do so. Jesus spoke the Sermon on the Mount, spoke parables and demonstrated miracles to many types of people and outcomes varied with some believing and others not believing.
Natural understanding and wisdom will not be sufficient for a fuller understanding of God.
Context for 1 Corinthians Chapter 2:
1 Corinthians 2:1-5 | ESV | And I, when I came to you, brothers, did not come proclaiming to you the testimony of God with lofty speech or wisdom. 2 For I resolved to know nothing among you except Jesus Christ and him crucified. And I was with you in weakness and in fear and much trembling, 4 and my speech and my message were not in plausible words of wisdom, but in demonstration of the Spirit and of power, 5 so that your faith might not rest in the wisdom of men but in the power of God.
Verses 1-5 describe how the Apostle Paul won converts to Christianity at Corinth in Greece in the first century. Miracles were part of the persuasion. There were visible miracles. There was also a change of heart and a coming to heart-faith among Paul's hearers which were also miracles.
Theologies may vary but human will is not sufficient for a person to come to heavenly citizenship. God must grant mercy and pardon to the individual person. Scripture contains promises that God will not reject those who come to come [in sincerity and earnestness] and people ought to seek God, believe the Scriptures, repent, believe, etc.. However, ultimately, the Holy Spirit of God must do a work in changing a person from the inside out.
There are several sources for wisdom, philosophy and religion in the world. However, Jesus Christ was the only Incarnate manifestation of God on earth and the only sacrifice for sins by which individuals might be justly pardoned.