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How Do We Know Which Books Belong in the Bible? The Question of Canonicity

Updated: Mar 17

The Problem

The Bible is not a single literary work but a collection of sixty-six separate books written across a time span of about 1,500 years by more than thirty different authors, all of them “carried along by God” (2 Peter 1:20-21) so that what they wrote is “God-breathed” (θεόπνευστος), making us “complete” and “thoroughly equipped for every good work” (2 Timothy 3:16-17). Jesus Himself testified to the inviolability of Scripture (John 10:35).

The advantage of this situation is that our faith is not based on the say-so of one man, but it does raise the question of “canonicity” i.e. how do we know which books properly constitute Scripture and therefore belong in the Bible.

Proposed Solutions

There are two competing answers that usually given.

One view is that we know which books belong in the Bible by authoritative declaration of the church. The Roman Catholic church claims that it is the church that has on its own God-given authority defined the canon of the New Testament, finalizing their decision in this matter at the Synod of Hippo Regius (AD 393) and the Council of Carthage (AD 397). Without the ruling of the church in this matter, Christians cannot know what books comprise Scripture.

There are four problems with this view. First, no church or Jewish council ruled on which books comprise the Old Testament, yet Jesus and the other Jewish people of His day knew which ones, as is plain from the use of the Old Testament Scriptures as authority in the New Testament. And the first-century Jewish historian Josephus confirms for us that the thirty-nine books in our Old Testament was the complete OT canon [1], the one that Jesus called “all the Scriptures” (Luke 24:27). This shows quite plainly that no official declaration from faith leaders is need to establish canonicity.

Second, it is a colossal circular argument. The Roman Catholic church (falsely) claims that its authority is based on Jesus’ appointment of Peter as the rock on which the church is built (Matthew 16:18-19). The problem here is that if the Roman Catholic church is correct about their claims, then we cannot know that the Gospel According to Matthew is Scripture before the church’s proclamation, but we have no reason to accept the church’s authority to make such a proclamation before we know that the Gospel According to Matthew is Scripture! In other words, the Roman Catholic wants Scripture to prove the church’s authority but claims that Scripture is not authoritative until the church proclaims it so. It is an inescapable circular argument.

The third problem is that many early Christian leaders from the latter part of the first century onwards (the early church “fathers” to which the Roman Catholic appeals) quoted books of the New Testament as Scripture long before the church proclaimed them to be Scripture.

The final problem is that the Roman Catholic church in the 4th century and onwards had already adopted a false gospel and were no true church at all, and so their pronouncement on any matter is worthless.

Evangelical scholars have proposed a different approach. They suggest that the church gradually felt a need to canonize certain books. The reasons for this included such things as a need to have an authoritative Scripture, heretical challenges, and persecution [2]. Regarding this last, Köstenberger et al. suggest that the edict of the Roman emperor Diocletian in AD 303 that all sacred books of the Christians be burned “required believers to choose which books were part of Scripture and thus most worthy of preservation [3].” Köstenberger et al. assert that the church then judged the various candidates for inclusion according to specific major “criteria of canonicity [4],” comprising apostolicity (association with an apostle), orthodoxy (conformation to the church’s “rule of faith”), antiquity (whether the book was produced during apostolic times), and ecclesiastical usage (whether the book was already widely used).

However, this, too seems to be problematic. It seems to rest the choice of books on the subjective opinions of fallible men long who pondered the matter long after the apostles were dead. (The claim that Christians did not feel a need to decide on the authentic books until after Diocletian’s edict in AD 303 seems particularly troubling). Evangelical scholars hasten to add, therefore, that the church was not determining the canon – God did that – but were merely discovering the canon already decided upon by God:

Yet this seems to be a distinction without a difference; certainly God inspired certain books that together make up the Bible, but if we are dependent on fallible men to “discover” hundreds of years later which books those were, we should certainly have doubts as to whether they did it correctly or not. The actual difference between “determining” and “discovering” is passing difficult to see.

The Biblical Answer

First, we note that there is actually no legitimate question about the Old Testament canon. As we have seen, we know that the Old Testament used in Israel at the time of Jesus consisted of the thirty-nine books in our Old Testament today, and that Jesus referred to this as “all the Scriptures” (Luke 24:27 [6]). He would not have referred to these thirty-nine books as “all the Scriptures” if there were other existing books (such as the Apocrypha) that were also Scriptures.

The only issue, therefore, is the canon of the New Testament, and regarding this there is a third option and that is to go to the Bible itself. In the Bible there are three crucial passages on this issue. First, there is 1 Timothy 5:18:

For the Scripture says, “You shall not muzzle an ox while it treads out the grain,” and, “The laborer is worthy of his wages.”

Here, Paul quotes two passages, calling them both “Scripture.” The first is from Deuteronomy 25:4, but the second appears nowhere in the Old Testament; in fact, it comes from Luke 10:7. This means that even as books of the New Testament were being written, others of them were already considered to be Scripture. Paul, in fact, makes no attempt whatsoever to argue that the Gospel According to Luke is Scripture; he clearly expects his readers already to know and accept this fact [7].

Similarly, Peter writes,

[C]onsider that the longsuffering of our Lord is salvation—as also our beloved brother Paul, according to the wisdom given to him, has written to you, as also in all his epistles, speaking in them of these things, in which are some things hard to understand, which ignorant and unstable people twist to their own destruction, as they do also the rest of the Scriptures. (2 Peter 3:15b-16)

Here, Peter speaks of “all” of Paul’s epistles and “the rest of the Scriptures,” making it clear that Paul’s letters are, in fact, Scripture. He, too, makes no attempt to introduce or defend this claim, which indicates his readers already know and accept it, and his comment even suggests that Paul’s letters may already have been collected and circulated among the churches, so that Peter’s readers were familiar with them.

Now, if books of the New Testament were already considered without controversy to be Scripture before the New Testament was even completed, it seems clear that they must have received canonical status long before any church council had anything to say on the matter, and it is not reasonable to supposed this happened only to some of the New Testament books and not to the others.

The question then is how this happened. What conferred canonical status on the New Testament books at such an early time? Who had the authority to designate books as Scripture? There was, in fact, only one authority capable of doing so: the apostles themselves. These were the men chosen by Jesus Himself [8] to be the foundation of the church (along with the prophets that wrote the Old Testament Scriptures), the ones who were the authoritative leaders responsible for passing on the doctrines of the New Covenant [9].

Their time to do this in person was, of course, limited to their own lifetimes on Earth, as apostolic authority was not something that could be passed on to future generations [10]. But that was enough time to create and authorize all of the New Testament Scriptures, which among them contain all that we need to be “complete” and “thoroughly equipped for every good work” (2 Timothy 3:17); no other authoritative source of doctrine is needed or possible.

Furthermore, there are indications that the apostles did indeed intend that books of Scripture should be the means for the conveying the apostolic doctrine to future generations. Peter, for example, writes in 2 Peter 1:12-15:

For this reason I will not be negligent to remind you always of these things, though you know and are established in the present truth. Yes, I think it is right, as long as I am in this tent, to stir you up by reminding you, knowing that shortly I must put off my tent, just as our Lord Jesus Christ showed me. Moreover I will be careful to ensure that you always have a reminder of these things after my decease.

Here Peter points out that as long as he is alive, he can continue teaching the doctrine in person, but, with his impending death in view, he must provide some other means for the continuing teaching of this doctrine, and, in light of what he writes in his next letter, it seems undeniable that this “reminder” is written Scripture:

Beloved, I now write to you this second epistle (in both of which I stir up your pure minds by way of reminder). (2 Peter 3:1)

Paul, too, indicates that he has written the epistle to the Romans as a “reminder” (Romans 15:15).

The only viable conclusion from this is that the books of the New Testament were recognized as Scripture immediately upon publication [11], and were accepted as such by Christians because apostles themselves designated these books as Scripture [12]. This does not mean, of course, that everything an apostle wrote was Scripture, but only what they themselves designated as such. Indeed, Paul seems to indicate by his words in 1 Corinthians 14:37 that he knew when he was writing Scripture:

If anyone thinks himself to be a prophet or spiritual, let him acknowledge that the things which I write to you are the commandments of the Lord. (1 Corinthians 14:37)

The statement in 2 Corinthians 3:14b-15 may also bear upon this matter:

For until this day the same veil remains unlifted in the reading of the Old Testament, because the veil is taken away in Christ. But even to this day, when Moses is read, a veil lies on their heart. (2 Corinthians 3:14b-15)

Here, Paul is referring to the written Hebrew Scriptures, as he specifies they are read and that Moses is included, and thus he calls the written Hebrew Scriptures “Old Testament.” But, until and unless there is a written New Testament, there is no rationale for calling the sum total of existing written Scriptures the Old Testament. It is the same principle whereby what we now know as World War I used to be called the World War or the Great War. It was not called World War I until there was a World War II. So Paul’s statement in 2 Corinthians 3:14b-15 at least suggest that by that time there were New Testament books extant that were already accepted as Scripture.

These statements, then, which are within the New Testament itself, settle the matter of the canonicity of the New Testament books. It is true that at later times, the canonicity of some of the books (e.g. Hebrews, 2 Peter) were challenged for a variety of idiosyncratic reasons by some church leaders [13], but the suppositions of men a century or more later do not override the testimony that we have seen in the New Testament itself. All it shows is that early Christian leaders were by no means infallible, and their writings should not be considered authoritative.

So we have certainty about the canonicity of the thirty-nine books in our Old Testament and the twenty-seven books in the New Testament. Indeed, God built His church “on the foundation of the apostles and prophets, Jesus Christ Himself being the chief cornerstone” (Ephesians 2:20b). The prophets bequeathed to us the Old Testament Scriptures and the apostles bequeathed to us the New Testament Scriptures, God superintending the process so that we can be sure about what constitutes the “God-breathed Scripture” by which we are made “complete” and “thoroughly equipped for every good work.”



1. Josephus, Against Apion 1.8. In the same reference, Josephus affirms that books were written by Jewish authors since the time of Artaxerxes but that these were never accepted as Scripture – and that includes all of the books of the Apocrypha, which the Roman Catholic church wrongly claims is Scripture.

2. Köstenberger, Andreas J., L. Scott Kellum, and Charles S. Quarles. The Cradle, the Cross, and the Crown: An Introduction to the New Testament. Nashville, Tennessee: B&H Academic, 2009, p. 8. The authors state that they are using “the treatment by N. Geisler and W. Nix.”. (q.v. op.cit.)

3. ibid.

4. ibid., pp. 8-10

5. Geisler, Norman L. and William E. Nix. A General Introduction to the Bible. Revised and Expanded. Chicago: Moody Press, 1986, p. 221

6. “And beginning at Moses and all the Prophets, He expounded to them in all the Scriptures the things concerning Himself.” (Luke 24:27).

7. It is not necessary to assume a priori that 1 Timothy is Scripture for the significance of Paul’s quotation to stand, because it shows that Christians at the time 1 Timothy was written already considered the Gospel According to Luke to be Scripture, regardless of whether they considered 1 Timothy to be Scripture.

8. Mark 3:13-19 (note in particular v. 13.); Acts 1:2

9. Ephesians 2:20; Acts 2:4; 1 Corinthians 12:28; 2 Peter 3:2; Acts 16:4. Their authority is evident throughout the book of Acts.

10. Apostles had to have seen the incarnate Jesus (Acts 1:21-22; 1 Corinthians 9:1), so anyone from the mid-second century AD onwards is excluded.

11. Regarding ancient times, “publication” referred to the release of a document for public use. (The original meaning of the word “publication” was “the act of making publicly known.”)

12. The writings of the apostles (e.g. Matthew, John, Paul, Peter) were de facto authoritative. Writers who were not apostles would have been authenticated by apostles (e.g. Mark by Peter, Luke by Paul). Of course, not all writings from the apostolic era were authorized as Scripture. First Clement, for example, was never considered to be Scripture and so could not have been authorized as such by the apostles. As a point of general interest, according to Tertullian (ca. AD 160-220), Clement was consecrated as bishop by Peter, but that does not mean he was an actual disciple of Peter.

13. Geisler and Nix, op.cit., pp. 298-301

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