Augustine’s writings in reply to the Manichaeans are fairly uneven (at least so far, I’m not done with them yet). We get an interesting combination of solid apologetics/theology and odd allegorical speculation. As the editor points out in the introduction, these are not really the best place to start with Augustine. And yet, as Gerald Bray points out in his masterful Augustine on the Christian Life, despite his problems (including working from a sub-par Latin translation, as Jerome’s Vulgate had not been finished yet) Augustine usually lands somewhere good.
As one example, in Augsutine’s lengthy Reply to Faustus the Manichaean, we get one of his famous lines about the relationship between the church and Scripture that has since become a cornerstone of Roman Catholic apologetics:
“As regards our writings[Augustine’s], which are not a rule of faith or practice, but only a help to edification, we may suppose that they contain some things falling short of the truth in obscure and recondite matters, and that these mistakes may or may not be corrected in subsequent treatises. For we are of those of whom the apostle says: “And if ye be otherwise minded, God shall reveal even this unto you.” Such writings are read with the right of judgment, and without any obligation to believe. In order to leave room for such profitable discussions of difficult questions, there is a distinct boundary line separating all productions subsequent to apostolic times from the authoritative canonical books of the Old and New Testaments. The authority of these books has come down to us from the apostles through the successions of bishops and the extension of the Church, and, from a position of lofty supremacy, claims the submission of every faithful and pious mind. ” (Reply to Faustus, XI.5)
Again, this argument is involved and arcane, and comes (at least this quote comes) from one of Augustine’s not-best works. Still, I think it’s something worth reflecting on and worth a bit of further digging.