Who so mad as to say with Manichaeus, that it is a weak faith not to believe i Christ without a witness; whereas the Apostle says, “How shall they believe on Him of whom they have not heard? Or how shall they hear without a preacher?” [Rom 10:14]
That those things which were preached by the Apostle might not be contemned, nor thought to be fables, they are proved to have been foretold by the Prophets. For though attested by miracles, yet there would not have been wanting men to ascribe them all to magical power, had not such suggestions been overcome by the additional testimony of prophecy.
For none could suppose that long before He was born, He had raised up by magic prophets to prophesy of Him. For if we say to a Gentile, Believe on Christ that He is God, and he should answer, Whence is it that I should believe on Him? we might allege the authority of the Prophets. Should he refuse assent to this, we establish their credit from their having foretold things to come, and those things having truly come to pass. I suppose he could not but know how great persecutions the Christian religion has formerly suffered from the Kings of this world; let him now behold those very Kings submitting to the kingdom of Christ, and all nations serving the same; all which things the Prophets foretold. He then hearing these things out of the Scriptures of the Prophets, and beholding them accomplished throughout the whole earth, would be moved to faith.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Cont. Faust., 12, 45, and 13, 7