11 And, this being so, hear also just so many conditions and differences of the same Scriptures. For it must be that just so many meet us. For either any one has written profitably, and is not profitably understood by some one: or both take place unprofitably: or the reader understands profitably, whereas he, who is read, has written contrariwise. Of these the first I blame not, the last I regard not. For neither can I blame the man, who without any fault of his own has been ill understood; nor can I be distressed at any one being read, who has failed to see the truth, when I see that the readers are no way injured.
There is then one kind most approved, and as it were most cleansed, when both the things written are well, and are taken in a good sense by the readers. And yet that also is still further divided into two: for it does not altogether shut out error. For it generally comes to pass, that, when a writer has held a good sense, the reader also holds a good sense; still other than he, and often better, often worse, yet profitably. But when both we hold the same sense as he whom we read, and that is every way suited to right conduct of life, there is the fullest possible measure of truth, and there is no place opened for error from any other quarter.
And this kind is altogether very rare, when what we read is matter of extreme obscurity: nor can it, in my opinion, be clearly known, but only believed. For by what proofs shall I so gather the will of a man who is absent or dead, as that I can swear to it: when, even if he were questioned being present, there might be many things, which, if he were no ill man, he would most carefully hide? But I think that it has nothing to do towards learning the matter of fact, of what character the writer was; yet is he most fairly believed good, whose writings have benefited the human race and posterity.
Source: On the Profit of Believing (New Advent)