What is the Bible?

In our modern time, the Bible is revered by many and also disesteemed by many. It is divided into the Old Testament and the New Testament for the Christians. The Hebrews who reject Jesus keep the Old Testament portion. The 'Old Testament' name that was assigned to the Hebrew canon does not reflect its actual status because it implies that the Hebrew canon is obsolete. 

Matthew 5:17-18 DRB
(17)  Do not think that I am come to destroy the law, or the prophets. I am not come to destroy, but to fulfil.
(18)  For amen I say unto you, till heaven and earth pass, one jot, or one tittle shall not pass of the law, till all be fulfilled.
However, Jesus did not know the New Testament, as the New Testament accounts for His life, His ministry, and the correspondence of the Apostles to the Gentiles in which they explained the Gospel of Jesus according to the Hebrew canon and the teachings of Jesus. When Jesus makes declarations about the Scriptures, He refers to portions of the books that make up the Old Testament. Jesus speaks of the Law, the Prophets, and the Psalms which make up the Scriptures which are known as the Old Testament in the Christian world and the Tanakh by the Hebrews.

In John 5:39, Jesus says that the Bible testifies about Him. if we have to look for the main Character in the Hebrew canon, ADONAI YHWH ELOHIM stands out. Simply put, by inference from John 5:39, Jesus says that He is ADONAI YHWH ELOHIM. Also, by inference from John 5:39, the Old Testament discourses on what to do to have eternal life.

John 5:39-40 DRB
(39)  Search the scriptures: for you think in them to have life everlasting. And the same are they that give testimony of me.
(40)  And you will not come to me that you may have life.
Therefore, the Bible is a book that serves as the reference guide for the instruction of any man in any generation on the behaviors that are acceptable to God the Father.

Romans 15:4 KJ3
For as many things as were written before were written for our instruction, that through the patience and the encouragement of the Scriptures we might have hope.
Those who reject the Bible or disagree with an ordinance in it are quick to point out that it was written by men, or we were not around when the narrative took place. Nevetheless, from the point of view of  the New Testament, those who wrote the various pieces were inspired by God.

2 Timothy 3:16-17 DRB
(16)  All scripture, inspired of God, is profitable to teach, to reprove, to correct, to instruct in justice:
(17)  That the man of God may be perfect, furnished to every good work.