It stands to reason that for people to believe and trust the Bible, it is of utmost importance to be sure that amidst the texts written/inspired by God, there are no books or passages that do not come from God. It is also important for people to be sure that the Bible contains not only a part but all the messages that God has sent to mankind.
Fortunately, the present - day readers of the Bible can have this trust and certainty. In the course of the sixteen centuries in which the Bible was completed, the forty human authors did all they could to see to it that the collection of books that they considered written by God were both complete and reliable.
About 1500 before Christ when the first Bible books were written, people who believed that they were dealing with texts written by God have kept a list of all the writings that they considered originating from God. Such a list is called a canon. About 1500 before Christ after Moses had written the first five books of our present Bible, this canon consisted of five books: Genesis, Exodus, Leviticus, Numbers and Deuteronomy. These were the only canonical books in those days. They were mentioned in the list of books that were considered coming from God. Everybody agreed that besides these five books by Moses, there were no other texts that had come from God.
It is good that every Bible reader knows what criteria people have employed in the course of the centuries in deciding whether texts were canonical or not.
Of course, all texts coming from God have to be perfect in all respects. They have to demonstrate God's perfect qualities, among which His perfect knowledge and wisdom. This means that all canonical writings may only contain true information. It may never happen that Bible texts contradict each other. It may never happen that one Bible text conflicts with another Bible text.
Besides, all Bible books must deal with the main theme of the Bible - the sanctification of God's name among mankind and the realization of the ends that God had in mind when He created the earth and man. Canonical books must call on people to accept God's sovereignty and His right to rule the universe. People are also called upon to use their God-given freedom to submit themselves to Him and His ends, out of love for their creator.
Canonicity of Hebrew and Greek Scriptures
The Hebrew Scriptures, which were written between about 1500 before Christ and approximately 400 before Christ, had still another criterion with which it was possible to distinguish canonical books from non-canonical ones. Many of the earlier Bible books contained prophecies that, later on in time, could be fulfilled or not. The fulfillment of prophecies expressed in a book pleaded for its being canonical. When prophecies expressed in a book were never fulfilled, this was a clear proof that the book in question was not canonical.
About the year 400 before Christ, there was complete unanimity among the Jews as regards to which books had originated from God and consequently were canonical and which were not. In the centuries that followed, up to and including the time of Jesus Christ, this unanimity was never challenged. Between the 4th century before Christ and the 1st century after Christ, everybody also agreed that after about 400 before Christ, no new God-inspired Hebrew Scriptures were written. Up to the present day, the Jews have stuck to this vision on what is canonical and what is not.
Jesus himself also recognized the canonicity of the Hebrew Scriptures that we accept as canonical today. In his public speeches, he often quoted from them. His disciples and the authors of the Greek Scriptures also recognized the canonicity of what we consider nowadays as the Hebrew Scriptures. They also quoted frequently from them. Every time they wrote the well-known words as it is written, they referred to the well-known Hebrew canonical books.
This does not mean to say that in the first to fourth centuries before Christ, no excellent religious texts were written. Excellent books on God and religion are written in all centuries, including our own.
But the Jews have never recognized these books as canonical. Jesus Christ has never quoted any sentence from these books. Moreover, Jesus' disciples and the authors of the Greek Scriptures have never referred to them in any way.
In spite of all this, from the 3rd century onwards, the Roman Catholic Church has doubted whether they should consider a number of books written in the 4th, 3rd, 2nd and 1st centuries B.C. canonical or not. Until the middle of the 16th century, there was division and debate within the Catholic Church about the canonicity of eleven books and fragments of books written in the centuries mentioned. Because of the doubts that exist with respect to the canonicity of these books, the Catholic Church calls them apocryphal or deutero-canonical. Apocryphal means 'accepted by some Catholic theologians and rejected by others'. Deutero-canonical means 'only accepted by some people as canonical after many centuries of debate and not recognized by everybody as belonging to the Jewish canon from the beginning of their existence'.
At the council of Carthage in 397 after Christ, the Roman Catholic Church tried to end all divisions and to include the apocryphal or deutero-canonical books in its canon. This was done in spite of the fact that in the first canons of the 2nd and 3rd centuries after Christ (the canon of Muratori of about 170 after Christ, the canon of Irenaeus of 180 after Christ, the canon of Clemens of Alexandria of 190, the canon of Tertullianus written in the year 207, the canon of Origen written in the year 230), these apocryphal or deutero-canonical books are not included.
The council of Carthage at that time did not put an end to the discussion within the Roman Catholic Church. It continued until the council of Trent in 1546 when the Catholic Church finally decided to recognize the apocryphal books as canonical.
With regards to the canonicity of the Greek Scriptures, there has never been any difference of opinion among Christians.