Knowledge and understanding are not as neutral as we might suspect. Knowledge and understanding of the Scripture is first a moral attitude. Psalm 19 explains that the knowledge of God impossible to miss, but perpetually denied – as Romans 1 attests. Augustine’s apology is not to merely give evidences to his Manichean counterpart. He assumes that Faustus is able to see the beauty and glory of God in nature – he has, in fact, been born with this innate understanding.
The power of Augustine’s apology for the authority of the Scriptures stems from the fact that the apostles had been with Christ. They had committed their testimony to writing – isn’t this, after all, John’s argument at the beginning of his first epistle? The pseudo-prophet, Mani, had not even been alive at the time of the Incarnate Word. Thus, the Christian has confidence because those who had been with Jesus made permanent their testimony to the life, ministry, and teaching of the Christ.
“If you want to follow the authority of the scriptures, which is to be preferred to all the others, you should follow the authority that has come down to these times from the time of Christ’s presence, that has been preserved, handed on, and glorified in the whole world through the ministries of the apostles and through the certain succession of bishops in the sees” (Answer to Faustus, 33.9).
Before they can believe what is plain to every person, the Manichean must repent and believe God’s testimony. “Since you will not be able to do this – for, as long as you are such people, you will in no way be able to – at least believe that idea, which is naturally implanted in every human mind, at least if it is not disturbed by the wickedness of a perverse opinion, namely, that the nature and substance of God is utterly immutable, utterly incorruptible, and you will immediately no longer be Manicheans, so that sometime you might also be able to be Catholics. Amen” (Answer to Faustus, 33.9).