The Bible is a mystery book. It is a mystery book because it contains the Word of God. The Word of God is a mystery. It is a mystery which has been hidden from man over the ages. It is now revealed to us who are the followers of Jesus Christ. Those who believe in Jesus now possess this mystery of God. The Bible says that this mystery is Christ in us, The Hope of Glory. Hallelujah!
This kind of mystery can't be understood by the men of the world. The men of the world cannot understand what the Bible says. It is foolishness unto them. Yes, it says that they are fools because they refuse to acknowledge the existence of God. To such people, the Bible is a bunch of reasonable thoughts. But we know that this is life.
The well educated people of this world only have the knowledge of their senses which they gather from science and philosophy. They are well educated when it comes to carnal knowledge. They do not know spiritual knowledge. The Bible speaks the wisdom of God comparing spiritual things with spiritual ones. So, the Bible cannot be understood by educational knowledge. It is the Holy Spirit who teaches the Bible