Before your brain starts going down the wrong path, we are not talking about a weapon that shoots cannonballs when lit (that’s a cannon, with two n’s). The canon we are talking about this week is the Biblical canon, which is the list of books considered to be Scripture by the Christian community. Open up a Protestant Bible and look at the table of contents page, and you’re looking at a basic list of the Christian canon. If you happen to open up a Roman Catholic Bible, you’ll likely see some extra books, called the Apocrypha, which most Christians have determined to be outside the approved canon of Scripture.
The biggest question people have when pondering the canon of Scripture is why those books are in and others didn’t make the cut. We do not have much knowledge on how the Old Testament came to be put together since it is considerably older, but it took over 200 years for the church to decide and agree on the books to include in the New Testament! The first proposed canon was in 144 A.D. by a guy named Marcion. However, he messed it up and took out any references to the Old Testament and changed some other doctrine, so his canon was rejected. The first somewhat official canon was put together around 200 A.D., but it was still not quite right. Half a century later another guy gave it a shot, and he was getting closer. Then, in the 4th century, the church decided to get a whole bunch of leaders and theologians together to work it out. The final canon we have today was decided on in 367 and reaffirmed in 397.
The key aspects they considered when forming the canon was what they called apostolicity - whether it came directly from an apostle of Christ. This is why certain books took longer to be approved for the canon, since not all books are clear on who authored them. The book of Hebrews is the main example of this, but there was debate over 1 and 2 Peter, James, and Revelation as well.
The canonization of Scripture is important because it finalized what books were to be considered important and which are not. Occasionally we see other uncanonized documents surface, such as the gospel of Thomas and others, but we as Christians trust the work done by the church fathers so many centuries ago that only the books included in our Bible are what God intended to be there. Because of that, we can trust that “All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness, so that the servant of God may be thoroughly equipped for every good work.” (2 Timothy 3:16-17)