In the first two parts of this series, we saw that the text of the Bible has been reliably preserved through the centuries of handwritten copying and that our modern translations of the Bible reliably express the meaning of the original-language texts. In this article, we consider the reliability of what is called the canon (“rule,” “standard”) of the Bible—that is, the standard list of books that are included in the Bible as inspired Scripture with divine authority for the Christian church. To explain the complex issues as simply as possible, we will offer some answers to frequently asked questions.

1. What qualifies some books to be part of the canon and other books not?

Two qualifications are met by the books of the Bible and no others. (1) They are written texts inspired by God through prophets or apostles (including books written on their behalf by trusted associates). Inspired oral preaching that was not written down is not Scripture. (2) Christians recognized them as Scripture early in church history and have used them as authoritative ever since. Thus, so-called “lost” texts that were unavailable for most of history are not part of the canon, even if they might be authentic. This is because by canon is meant the inspired books that have been available to guide Christians ever since efforts to collect them began. For example, the Old Testament refers to just a few books that might have been inspired but have never been part of any collection of Scripture and have not been read for thousands of years; such books, even if they were inspired, by definition are not part of the canon. Likewise, Paul mentions an earlier letter to the Corinthians that has never been part of the church’s collection of his writings (1 Cor. 5:9) and remains unknown; thus, even if it were to be discovered and authenticated (which is extremely unlikely), we would not add it to the canon of Scripture. It does not qualify for inclusion because it has not been available to the church for use as Scripture all along like the New Testament books.

For more on this question, see our article Why Are Some Books Considered Scripture and Others Not?

2. On what basis do Christians accept the books of the Old Testament as Scripture?

Jesus and his apostles had many disagreements with the Pharisees, the Jewish teachers who were the forerunners of rabbinical Judaism. However, one thing on which they did not disagree was the Jewish Scriptures. Unlike the Sadducees, who regarded only the Pentateuch (Genesis through Deuteronomy) as Scripture, the Pharisees as well as Jesus and his followers accepted such books as the Psalms and Isaiah as Scripture. Jesus stated that everything written about him “in the Law of Moses and the Prophets and the Psalms must be fulfilled” (Luke 24:44). This statement reflected a fairly standard Pharisaic division of their Scriptures into three categories that included the Pentateuch, the writings of and about the prophets (which included the historical books), and the wisdom writings that were dominated by the book of Psalms. By the first century, Jews were stating that there were 22 books in Scripture, corresponding to the 22 letters of the Hebrew alphabet. Because they numbered the books differently than we do (e.g., 1-2 Samuel as one book, 1-2 Kings as one, etc., and the twelve “Minor Prophets” as one), their 22 books corresponded to the 39 books of the Protestant Old Testament.

3. What about the Apocrypha?

Non-Protestant Christians accept a smattering of Jewish books written during the period of 250 BC to AD 100 that neither Protestants nor Jews accept as Scripture (e.g., 1 and 2 Maccabees, Judith, Tobit, Wisdom of Solomon, and Sirach). The status of these books is at most a minor issue, since they contain little of doctrinal significance that differs from the Bible. It is worth noting that Catholics call these books “deuterocanonical,” meaning that they are in effect a second-class group of Old Testament writings. In other words, they also draw a line between these books and those everyone agrees are Scripture. They did not officially state that the Apocrypha was Scripture until the Council of Trent in the sixteenth century, when a few verses seemed to support such Catholic doctrines as purgatory and praying the for dead. In support of the Protestant position, we may point out that one of the books in the Apocrypha admits it was written during a time that “there was no prophet seen in Israel” (1 Macc. 9:27; see also 4:46; 14:41). Without prophets, they could have no inspired Scripture.

4. How do we know the right books are in the New Testament?

Among Christians who accept Peter and Paul as apostles, there is virtually no argument about which Christian books belong in the canon of the New Testament. Catholics, Orthodox, and Protestants agree on the same 27 books (4 Gospels, Acts, 13 epistles bearing Paul’s name, 8 general epistles, and Revelation). A few churches accept these books but have additional texts, such as the epistles of Clement accepted by the Coptic Church. Despite such idiosyncrasies of smaller ethnic churches, the 27-book canon may be viewed as the consensus position of Christianity. Even modern heretical sects such as Mormons and Jehovah’s Witnesses accept those 27 books as Scripture. Again, the reason Christians accept these books as Scripture is that they were written by apostles or authors who worked on their behalf (such as Mark writing down what Peter said) and have been preserved for us through the centuries, recognized and continuously used by Christians as Scripture.

5. What about the Gnostic writings?

The term Gnostic refers to a variety of ancient teachings and writings that generally claimed to impart secret or esoteric (hidden) religious truth. Such Gnostic writings as the Gospel of Thomas were definitely not written by apostles or their associates (virtually no one thinks the apostle Thomas wrote that “Gospel”) and are dated by nearly all scholars to the second century, not the time of the apostles in the first century. Simply reading these books is usually enough for Christians to understand why they are not in the canon. The Gospel of Thomas, for example, concludes with a quote of Jesus supposedly telling Peter that Mary Magdalene could tag along with them because if she was faithful she would become male, and then she would be fit for the kingdom of heaven!

6. Is the canon of Scripture closed?

The Old Testament canon is obviously closed because the Old Testament era came to an end when Jesus arrived. The New Testament, as the collection of writings produced by the apostles and their co-workers, is obviously complete because the apostles have been dead for nearly two thousand years. Since to be accepted into the canon a book must have been available to function as part of the standard Scriptures throughout church history, we may say confidently that the Bible is complete.

Of course, if God wanted to call new prophets or apostles and inspire them to write new scriptures, he could. However, the burden of proof would be on any such text. We would need to have very good reasons to accept it as genuinely inspired, and it would need to agree with the teachings of the Bible. In practice, none of the alleged scriptures that have appeared since the Bible—such as the Qur’an, the Book of Mormon, or Mary Baker Eddy’s Science and Health—has passed these tests. So, for all practical purposes, Christians are right to conclude that the canon of Scripture is in fact closed.