The canon of Scripture is the list of all the books that belong in the Bible. The Bible, the Apocrypha and history all testify to the historical development of the Old Testament canon.
Scholars have attacked Christianity by claiming that Christians don’t know which books should belong to the New Testament canon and which ones shouldn’t. If we don’t know the answer to why these 27 books, then we do have a problem. But it’s not the Achilles heel of Christian faith that critics claim it is. We Christians do have an answer.