Faustus rejects Christ's declaration that He came not to destroy the law and the prophets but to fulfill them, on the ground that it is found only in Matthew, who was not present when the words purport to have been spoken. Augustine rebukes the folly of refusing to believe Matthew and yet believing Manichæus, and shows what the passage of scripture really means.
Source: Reply to Faustus the Manichaean (New Advent)