An interesting article at ThinkTheology.co.uk draws together some useful quotations from St. Augustine on the inspiration of scripture.
The quotations come from Augustine’s letter 82, addressed to St. Jerome himself.
For I confess to your Charity that I have learned to yield this respect and honour only to the canonical books of Scripture: of these alone do I most firmly believe that the authors were completely free from error. And if in these writings I am perplexed by anything which appears to me opposed to truth, I do not hesitate to suppose that either the manuscript is faulty, or the translator has not caught the meaning of what was said, or I myself have failed to understand it.
As to all other writings, in reading them, however great the superiority of the authors to myself in sanctity and learning, I do not accept their teaching as true on the mere ground of the opinion being held by them; but only because they have succeeded in convincing my judgment of its truth either by means of these canonical writings themselves, or by arguments addressed to my reason.
I believe, my brother, that this is your own opinion as well as mine. I do not need to say that I do not suppose you to wish your books to be read like those of prophets or of apostles, concerning which it would be wrong to doubt that they are free from error … (82.3)
But you will say it is better to believe that the Apostle Paul wrote what was not true, than to believe that the Apostle Peter did what was not right. On this principle, we must say (which far be it from us to say), that it is better to believe that the gospel history is false, than to believe that Christ was denied by Peter; and better to charge the book of Kings with false statements, than believe that so great a prophet, and one so signally chosen by the Lord God as David was, committed adultery in lusting after and taking away the wife of another, and committed such detestable homicide in procuring the death of her husband.
Better far that I should read with certainty and persuasion of its truth the Holy Scripture, placed on the highest (even the heavenly) pinnacle of authority, and should, without questioning the trustworthiness of its statements, learn from it that men have been either commended, or corrected, or condemned, than that, through fear of believing that by men, who, though of most praiseworthy excellence, were no more than men, actions deserving rebuke might sometimes be done, I should admit suspicions affecting the trustworthiness of the whole oracles of God. (82.5)
The translation is the 19th century one, which may be found online here.
I have never collected ancient statements concerned with the inspiration of scripture; doing so would certainly be an interesting and useful exercise. But I do recall another passage of Augustine on scripture which deserves quotation here. It is from De genesim ad litteram (On Genesis, literally expounded), book 2, chapter 9:
It is frequently asked what our belief must be about the form and shape of heaven according to Sacred Scripture. Many scholars engaged in lengthy discussions on these matter, but the sacred writers with their deeper wisdom have omitted them. Such subjects are of no profit for those who seek beatitude, and, what is worse, they take up precious time that ought to be given to what is spiritually beneficial. What concern is it of mine whether heaven is a sphere and the earth is enclosed by it and suspended in the middle of the universe, or whether heaven like a disk above the earth covers it on one side?
But the credibility of Scripture is at stake, and as I have indicated more than once, there is danger that a man uninstructed in divine revelation, discovering something in Scripture or hearing from it something that seems to be at variance with the knowledge that he has acquired, may resolutely withhold his assent in other matters where Scripture presents useful admonitions, narratives, or declarations. Hence, I must say briefly that in the matter of the shape of heaven the sacred writers knew the truth, but that the Spirit of God, who spoke through them, did not wish to teach men these facts that would be of no avail to their salvation.
This translation is as translated by J.H.Taylor, 1982.
All of this is sensible stuff.
We must always remember that there are only two groups of Christians; those whose ultimate authority is the word of scripture, and those who have come to think it is not the ultimate authority, and so, inevitably, give the last word elsewhere — invariably to the world, then to the flesh, and finally to the devil. It is not enough to mean well; we must think well also. It isn’t very clever to be so clever that we talk ourselves out of salvation.