Speaking of his knowledge of, and assurance of, the reliability of the New Testament canon, Jonathan Edwards wrote the following which privileges extra-biblical sources in a way to contradict many Reformed formulations of Sola Scriptura:
Several of the first writers of Christianity, have left us, in their works, catalogues of the sacred books of the New Testament, which, though made in countries at a vast distance from each other, do very little differ. Great were the pains and care of those early Christians, to be well assured what were the genuine writings of the apostles, and to distinguish them from all pretended revelations of designing men, and the forgeries they published under sacred titles. Thus, when a presbyter of Asia had published a spurious piece, under the name of Paul, he was immediately convicted, and notice of the forgery was soon conveyed to Carthage and the churches of Africa.
Hence it follows, that the primitive Christians are proper judges to determine what book is canonical, and what not. For nothing can be more absurd than to suppose, in those early ages, an agreement so universal, without good and solid foundation: or, in other words, it is next to impossible, either that so great a number of men should agree in a cheat, or be imposed upon by a cheat. But there are some particular circumstances that make the inference more clear as to the Christian books, than others; such as the prodigious esteem the books at first were received with; the constant use that was made of them in their religious assemblies; the translations made of them very early into other languages, &c.
The omission of a book in some one or two particular catalogues, cannot, with any reason, be urged against its canonical authority, if it be found in all, or most of the others, and any good reason can be assigned for the omission, where it occurs. Thus, for instance, the Revelation is omitted, either perhaps because it was not known to the author, or its credit was not sufficiently established in the country where he lived; or perhaps, which may be as probable as the other, because it being so full of mysteries, few or none were judged proper or able to read it to any purpose. This was certainly the case in England: this book being, for this reason, omitted in the public calendar for reading the Scriptures, though it be received into the canon. If, therefore, these, or any such good reasons, can be assigned or the omission of a book in a particular catalogue, it will be very unfair to infer that such book is apocryphal, especially when it is to be found, in many or most other catalogues.
The catalogues drawn up by Athanasius, bishop of Alexandria (A.D. 315,)—by Epiphanius, bishop of Salamis, (A.D. 370,)—by Jerome, of Dalmatia, (A.D. 390,)—by Augustine, bishop of Hippo (A.D. 394,)—by forty-four bishops assembled in the 3d council of Carthage, (A.D. 416,) were perfectly the same with ours now received. (On the Scriptures, chapter VI, §§ 8-11 in The Works of Jonathan Edwards [2 vols.; Edinburgh: The Banner of Truth Trust, 1974], 2:475, emphasis added)
One also finds it interesting that Edwards would cite Augustine and the council of Carthage. While they agreed with Edwards on the 27 books of the New Testament, they accepted a larger Old Testament than his Old Testament canon.