A - Thanks for the question.
The word "canon" means rule or measure. In terms of the Bible, it specifically refers to the list of the books that are inspired by the Holy Spirit and are thus deemed Sacred Scripture. Therefore, the books in the Bible are called canonical and the books that are not determined to be inspired by God are extra-canonical. How did this determination come about? This is what we will examine here.
Almost all Christians believe in the truths found in the Bible, but there are two different lists of what belongs in the Old Testament - the list used by the Catholic Church (and most Eastern Orthodox) and the list used by most Protestants. The Protestant canon contains 7 fewer books than the Catholic canon. These 7 books are called the deuterocanon ("second" canon). These books were given the name deuterocanon because a few hundred years ago we did not have copies of them in Hebrew and they were not part of some Hebrew Bibles. Thus, they were deemed to be part of a second canon written in Greek. We now have manuscripts, or partial manuscripts, that show that most, if not all, of the books were written in Hebrew or Aramaic.
Protestants call these seven books apocryphal, meaning that they are not part of the canon of the Bible.
Thus, we have two different lists of what books should be part of the Old Testament.
Many Christians have never reflected on the history of the Bible and how it came to be. They just assume that it is authoritative and we should consider all the books in the Bible as Sacred Scripture.
Here is a brief history of how the Bible came to be put together.
- Jesus came and taught his disciples. During the time of Jesus there were several different lists of the Old Testament Scriptures in different Jewish groups.
- Jesus' disciples spread his message orally for years.
- His disciples started to write down the messages of Jesus.
- During the early Church some Jews decided to try and set the OT canon. This failed to solve the issue of different lists for different Jews. Thus, the Jewish canon was never decided authoritatively by the Jews. Once Jesus came, the Jews no longer had the authority to set the Jewish canon for Christians.
- Different local Churches started to compile these different writings. Many of the lists differed from one another dramatically.
- The Catholic Church started to discern, through the guidance of the Holy Spirit, what was inspired and what was not. This goes for both the New Testament and the Old Testament.
- Several Catholic Councils of Bishops declared the list of Scripture as we have it today - Council of Hippo, 393 A.D. / Carthage, 397 A.D. / Carthage 419 A.D.
- This list remained fixed through hundreds of years.
- Saints, bishops, Popes and the Council of Florence (1442 A.D.) affirmed the list.
- The list is challenged seriously for the first time by Martin Luther, when he rejects the 7 deuterocanonical books. He decides to throw them out of his new canon. Thus, the Protestant Bible is first born in the 1500s. He bases this decision on faulty evidence:
- He claimed they contained doctrines contrary to the rest of Scripture (rather, he didn't like the teachings that supported Catholic doctrines).
- He claimed that the Jews had set this canon (rather, there were still different lists by different Jewish groups).
- He claimed that only the Scriptures written in Hebrew were of the canon (rather, he didn't have access to the documents that show they were written in Hebrew).
- The list of Sacred Scripture is put down dogmatically in the Council of Trent, which followed the Protestant Reformation. This is because dogma is usually not declared unless first challenged seriously.
Here is some other evidence in favor of the Catholic list of the OT canon.
- God never gave the Jews a way to settle the debate over what books should be in the Jewish canon.
- In the time of Jesus there were several different groups of Jews with different lists of their Scriptures:
- The Samaritans and Sadducees accepted the law but rejected the prophets and writings.
- The Pharisees accepted all three.
- Some Jews used the Greek version called the Septuagint. This is the list that the Catholic Church uses. Textual analysis indicates that most of the New Testament writers quote most often from the Septuagint in the NT, therefore indicating that they used and accepted it.
- Some smaller groups with different lists.
- The early Christian Church Fathers accepted the deuterocanonical books as inspired.
I know this is the Cliff Notes version. If you want more details, I highly recommend the book - Where We Got the Bible by Henry Graham.
I hope this helps.