2 Augustine replied: As I said a little ago, when these men are beset by clear testimonies of Scripture, and cannot escape from their grasp, they declare that the passage is spurious. The declaration only shows their aversion to the truth, and their obstinacy in error. Unable to answer these statements of Scripture, they deny their genuineness. But if this answer is admitted, or allowed to have any weight, it will be useless to quote any book or any passage against your errors.
It is one thing to reject the books themselves, and to profess no regard for their authority, as the Pagans reject our Scriptures, and the Jews the New Testament, and as we reject any books peculiar to your sect, or any other heretical sect, and also the apocryphal books, which are so called, not because of any mysterious regard paid to them, but because they are mysterious in their origin, and in the absence of clear evidence, have only some obscure presumption to rest upon; and it is another thing to say, This holy man wrote only the truth, and this is his epistle, but some verses are his, and some are not.
And then, when you are asked for a proof, instead of referring to more correct or more ancient manuscripts, or to a greater number, or to the original text, your reply is, This verse is his, because it makes for me; and this is not his, because it is against me. Are you, then, the rule of truth? Can nothing be true that is against you? But what answer could you give to an opponent as insane as yourself, if he confronts you by saying, The passage in your favor is spurious, and that against you is genuine?
Perhaps you will produce a book, all of which can be explained so as to support you. Then, instead of rejecting a passage, he will reply by condemning the whole book as spurious. You have no resource against such an opponent. For all the testimony you can bring in favor of your book from antiquity or tradition will avail nothing. In this respect the testimony of the Catholic Church is conspicuous, as supported by a succession of bishops from the original seats of the apostles up to the present time, and by the consent of so many nations.
Accordingly, should there be a question about the text of some passage, as there are a few passages with various readings well known to students of the sacred Scriptures, we should first consult the manuscripts of the country where the religion was first taught; and if these still varied, we should take the text of the greater number, or of the more ancient. And if any uncertainty remained, we should consult the original text. This is the method employed by those who, in any question about the Scriptures, do not lose sight of the regard due to their authority, and inquire with the view of gaining information, not of raising disputes.
Source: Reply to Faustus the Manichaean (New Advent)