One of the big ideas of Dan Brown's Da Vinci Code concerned the canon of Scripture. He picked up on a popular idea that Constantine brought to an end a free-flowing Christianity and imposed a certain orthodoxy on the church -- including a New Testament canon. The truth is, that "official" list had been in the process of development for some time. In fact, Marcion's attempt to create a canon served as the real impetus -- and his canon was much smaller than that embraced by the wider church. In large part that was due to a strong anti-Judaism present in his theology and much of Gnostic thought.
So, how do you decide what belongs in this listing of authoritative books? The early Christian leaders turned to a number of criteria, including apostolic authorship and perceived age. Of course, since many documents claimed to be early and of apostolic origin, that proved insufficient. Thus, creedal formulations began to emerge -- what have come to be known as the Rule of Faith. The key to discerning what belonged in the canon was its content -- did it match what at least some Christians considered orthodoxy. Everything, including New Testament Scripture, had to be measured against this standard.
The Rule of Faith proved necessary because heterodox and orthodox alike made use of the same texts. To refute heterodox opponents the church developed the Rule of Faith, a summary of the Christian faith that emerged out of the Scriptural witness, and then helped form the New Testament canon. Though there is a strong relationship between the Rule and the New Testament, its origins can be found instead in oral tradition. Kurt Aland made the following comment on this rule.
It presents the deposit of the developing faith possessed by the church. Its content accordingly changed, even when the words remained the same for a longer period of time or altogether. The formula attained life, indeed its real existence only through interpretation. It presupposes a definite and continuously developing basic prior understanding, even though the regula fidei was only one of the normative points in which the church of the second century saw the pure doctrine being guaranteed. [Kurt Aland, A History of Christianity: From the Beginnings to the Threshold of the Reformation (History of Christianity) (Volume 1), p. 115].
Though it was not the only guarantee, adherence to this Rule of Faith was seen by many as constituting orthodox Christian faith.
Because both heretics and orthodox quoted from and used Scripture, Tertullian, in his Prescriptions Against Heretics, insisted that one should not argue with the heterodox from Scripture. To do so was a fruitless venture. Furthermore, since the orthodox church had ownership of the Scriptures from the beginning, they alone could argue from Scripture. Thus, if one was to argue from Scripture, one must first affirm the Rule of Faith. Tertullian insisted that "This Rule, taught (as will be proved) by Christ, allows of no questions among us, except those which heresies introduce and make heretics." Therefore, ifs you did not contradict this Rule of Faith, you could discuss as much as you liked. [Tertullian, "Prescription Against Heretics," in S.L. Greenslade, ed., Early Latin Theology, (Philadelphia: Westminster Press, 1956), 39-41].
So, what did this precursor to the Apostles Creed look like? Here is Tertullian's version, which emerged at the beginning of the third century.
The Rule of Faith--to state here and now what we maintain--is of course that by which we believe that there is but one God, who is none other than the Creator of the World, who produced everything from nothing through his Word, and sent forth before all things; that this Word is called his Son, and in the Name of God was seen in divers ways by the patriarchs, was ever heard in the prophets and finally was brought down by the Spirit and Power of God the Father into the Virgin Mary, was made flesh in her Womb, was born of her and lived as Jesus Christ; who thereafter proclaimed a new law and a new promise of the kingdom of heaven, worked miracles, was crucified, on the third day rose again, was caught up into heaven and sat down at the right hand of the Father; that he sent in his place the power of the Holy Spirit to guide believers; that he will come with glory to take the saints up into the fruition of the life eternal and the heavenly promises and to judge the wicked to everlasting fire, after the resurrection of both good and evil with the restoration of their flesh.
You can see many of the elements that emerge as the Apostles Creed. The concern is the oneness of God, who is Creator and the revelation of that God through the Word made flesh. The Holy Spirit guides the believers to eternal life. For a community not yet in control of their destiny that promise of heaven stands tall.
We live in a different context, with different concerns, but how do we express our faith in a way that is coherent and faithful? We look to Scripture -- though with a critical eye -- but how do we know what texts we should look to? Who decides the canon? Is it open or closed? If open, on what basis do we add books?