For as he thinks within himself, so he is...
The Bible tells man what to think, how to think, and why to think. It tells us of the benefits of right thinking and the consequences of wrong thinking. It presents the foundation of right thinking, which is the knowledge of God Himself, and the corresponding knowledge of man himself.
The Bible is the foundation for right thinking because it presents to us the truth about God, and the truth about God becomes the mirror and backdrop from which we learn the truth about man, which is the truth about ourselves. We will never know the full truth about ourselves until we know the truth about God; and an important facet of knowing the truth about God is the belief and its consequential acceptance of what the Bible says about Him.
Truth is reality, what is real, as compared to what is imagined, desired, or fantasized. The Bible presents life and existence (now and eternally) as it really is, not as we want it to be. The Bible presents God as He really is, not as we want Him to be or imagine Him to be. The Bible presents man (all of us) as he really is, not as we want him to be or imagine ourselves to be.
For a man to be right before God and to right with God, he must first think rightly about God and rightly about himself. Only the truth of God, found in the pages of the Bible can lead a man to the path and down the path to be right with God. God has given us the Bible for just that purpose, as He wants us to be right with Him.
Do you want to be right with God? Do you want to think rightly about God and about yourself? Then turn to the Bible, for it is there that you will find the foundation for right thinking, the truth.