4 Manichæus indeed was not a prophet of Christ, but calls himself an apostle, which is a shameless falsehood; for it is well known that this heresy began not only after Tertullian, but after Cyprian. In all his letters Manichæus begins thus: "Manichæus, an apostle of Jesus Christ." Why do you believe what Manichæus says of Christ? What evidence does he give of his apostleship? This very name of Christ is known to us only from the Jews, who, in their application of it to their kings and priests, were not individually, but nationally, prophets of Christ and Christ's kingdom.
What right has he to use this name, who forbids you to believe the Hebrew prophets, that he may make you the heretical disciples of a false Christ, as he himself is a false and heretical apostle? And if Faustus quotes as evidence in his own support some prophets who, according to him, foretell Christ, how will he satisfy his supposed inquirer, who will not believe either the prophets or Faustus? Will he take our apostles as witnesses? Unless he can find some apostles in life, he must read their writings; and these are all against him.
They teach our doctrine that Christ was born of the Virgin Mary, that He was the Son of God, of the seed of David according to the flesh. He cannot pretend that the writings have been tampered with, for that would be to attack the credit of his own witnesses. Or if he produces his own manuscripts of the apostolic writings, he must also obtain for them the authority of the churches founded by the apostles themselves, by showing that they have been preserved and transmitted with their sanction. It will be difficult for a man to make me believe him on the evidence of writings which derive all their authority from his own word, which I do not believe.
Source: Reply to Faustus the Manichaean (New Advent)