11 You ask me to show what Moses wrote of Christ. Many passages have already been pointed out. But who could point out all? Besides, when any quotation is made, you are ready perversely to try to give the words another meaning; or if the evidence is too strong to be resisted, you will say that you take the passage as a sweet fish out of the salt water, and that you will not therefore consent to drink all the brine of the books of Moses. It will be enough, then, to take those passages in the Hebrew law which Faustus has chosen for criticism, and to show that, when rightly understood, they apply to Christ.
For if the things which our adversary ridicules and condemns are made to prove that he himself is condemned by Christian truth, it will be evident that either the mere quotation or the careful examination of the other passages will be enough to show their agreement with Christian faith. Well, then, O you full of all subtlety, when the Lord in the Gospel says, "If you believed Moses, you would believe me also, for he wrote of me," there is no occasion for the great perplexity you pretend to be in, or for the alternative of either pronouncing this verse spurious or calling Jesus a liar.
The verse is as genuine as its words are true. I preferred, says Faustus, to attribute falsehood to the writers, rather than to the Author of truth. What sort of faith can you have in Christ as the author of truth, when your doctrine is that His flesh and His death, His wounds and their marks, were feigned? And where is your authority for saying that Christ is the author of truth, if you dare to attribute falsehood to those who wrote of Him, whose testimony has come down to us with the confirmation of those immediately succeeding them?
You have not seen Christ, nor has He conversed with you as with the apostles, nor called you from heaven as He did Saul. What knowledge or belief can we have of Christ, but on the authority of Scripture? Or if there is falsehood in the Gospel which has been widely published among all nations, and has been held in such high sacredness in all churches since the name of Christ was first preached, where shall we find a trustworthy record of Christ? If the Gospel is called in question in spite of the general consent regarding it, there can be no writing which a man may not call spurious if he does not wish to believe it.
Source: Reply to Faustus the Manichaean (New Advent)