What is the Bible? This Barnes Bible Chart is a very good starting point to consider this important question. While there are many associated questions, this question is paramount in beginning to understand the Bible's purpose.
In an of itself, the chart is complete, but I think it appropriate to fully quote each verse...
James, Chapter 1 (World English Bible)
23 For if anyone is a hearer of the word and not a doer, he is like a man looking at his natural face in a mirror; 24 for he sees himself, and goes away, and immediately forgets what kind of man he was.
Hebrews, Chapter 4 (WEB)
12 For the word of God is living and active, and sharper than any two-edged sword, piercing even to the dividing of soul and spirit, of both joints and marrow, and is able to discern the thoughts and intentions of the heart.
Jeremiah, Chapter 29 (WEB)
29 “Isn’t my word like fire?” says Yahweh; “and like a hammer that breaks the rock in pieces?
The Bible will change your life. Believe that, because its true! When you read and practice its instruction you will change. I know this from personal experience! God speaks to your mind, your heart and how you actually live your life.
Do yourself a favor, consider these things and take God at HIS word; I promise you- YOU will never be the same!!!