D. F. Strauss once declared that the question of how to authenticate the biblical canon was the "Achilles heel" of Reformed/Protestant Christianity. After all, when it comes to the New Testament, how do we know for sure that we have the right 27 books? Why not 26 books? Or 28? And if we cannot adequately answer this question about the canonical boundaries of the New Testament, then on what grounds could we ever appeal to the content of the New Testament? Certainly, there can be no New Testament theology if there is no such thing as a "New Testament" in the first place. Thus, questions about the canon can take on more foundational significance than other types of questions. It is one thing for a person to question the meaning of a given passage (and whether it says what we think it says), but it is entirely another to question whether that passage belongs in the Bible in the first place. The question of the canon, therefore, is at the very center of how we establish biblical authority. Unless the church can offer a coherent response to such critical attacks, then Strauss may be all too right-the canon issue could become the single thread that unravels the entire garment of our faith.
How, then, are the boundaries of the canon established? If we are to have certainty concerning the extent of the New Testament canon, then we must hear from the only one who has the authority to tell us which books belong there: God himself. He is the ultimate "canon." But, how does God "speak" to us? We observe in the Scriptures that God "speaks" to his people through three different media: words (the Scripture itself), historical events (redemptive history), and people (personal experience). Each of these different media, when understood correctly and understood along with the other two, bears the authority of God's revelation. Let us consider each of them in order.
1. Scripture. In any discussion of the authority and extent of the canon, the fundamental testimony that must not be ignored is the testimony of the canon itself, the very Word of God. Unfortunately, because the extent of the canon is the very thing in question, many refuse to consider the content of the canon in their discussion of its authenticity. However, it is here that we will take our cue from the reformers and their understanding of the self-attesting (autopistic) nature of Scripture. The reformers argued that the Scriptures do not become authoritative only after they have been verified and approved by historical investigations, but rather are authoritative in their own right, and thus provide the only proper epistemological starting point for all intellectual investigations (historical or otherwise). Turretin notes, "Thus Scripture, which is the first principle in the supernatural order, is known by itself and has no need of arguments derived from without to prove and make itself known to us." In other words, the canon internally bears the "marks" of a divine book and evidences itself to be from God. We know which books are in the canon through the canon itself. Thus, the authority of the canon is not simply the conclusion of our investigation but supplies the very foundation and guiding principles of our investigation. Consequently, we approach the historical evidence and our personal experience in light of, and in submission to, the revealed word of God.
2. Redemptive History. God not only speaks through his written Word, but he also speaks through redemptive history, through his mighty acts done on behalf of his people (Exod. 14:31; John 8:38, 20:30-31; Acts 2:22; Heb. 1:1-4). He has chosen to deliver his Word to his people not from golden tablets lowered from heaven but through the activities and events of real history. Thus, if we are going to establish which canon is the true canon, then we must view the canon through the eyes of redemptive history-we must look to see God at work during the historical development of the canon. It is here that we examine the historical "facts" about the origins of the canon and see that we have good reasons to think that we have the right 27 books. There is not space here to enter into the historical details, but there is evidence that by the early second century the core of the New Testament canon-the four gospels and the thirteen epistles of Paul-was functioning as authoritative Scripture for the early church. This provided a strong foundation for the church to engage in further discussions about the books that some doubted (e.g., 2 Peter, Revelation, etc.), and to battle various heresies and the challenges of burgeoning apocryphal literature. In the end, we have solid historical reasons to think that the 27 books finally recognized by the church were authentic, originated from the age of the apostles, and bore divine authority. Of course, it is important to keep in mind that whenever we interpret historical evidence/events it is not to be done neutrally but is to be done in light of God's revealed Word. Thus, God can "speak" to us about the extent of the canon through the historical facts, but only in as much as those facts are interpreted through the lens of God's special revelation.
3. Personal Experience. God not only speaks through his written Word, and through redemptive history, but he also speaks through his Holy Spirit to the hearts of individuals (and to the corporate church). Thus, in order to know the true canon, we cannot simply know the historical facts (redemptive history) or the standard by which they are interpreted (Scripture), but we must also know ourselves and our response to these books because we are the ones doing the knowing. Thus, we are not talking about "subjectivism" here, per se, but are noting that one of the primary ways we know the true canon of Scripture is the manner in which the Holy Spirit testifies to us (and to the corporate, historical church) that these books are from God. It is clear that throughout the ages, both individual Christians and the church at large, have recognized the voice of their master in these 27 books (John 10:27).
All three of these media-Scripture, redemptive history, and personal experience-work together in a manner that makes them the one unified voice of God testifying to the authentic canon of the New Testament. We know we have the right books because the canon, as self-attesting Scripture, internally bears evidence that it is a divine book. We know we have the right books because historical investigations reveal much solid evidence that God was at work revealing and delivering these books to the New Testament church. And we know we have the right books because the Holy Spirit testifies in our hearts (and in the hearts of Christians throughout the ages) that these are his books and we recognize his voice. Thus, in the end, we know we have the right books because of the testimony of God himself.