1. In the six previous books, holy brother Ambrose, we have wrestled to the best of our ability against Celsus' criticisms of the Christians, and have done all in our power to avoid allowing anything to pass by untested and unexamined, and have left nothing to which we have not replied as well as we could. After calling on God through that same Jesus Christ who is accused by Celsus, asking that, as he is the truth, he may cause to shine in our hearts the arguments which can successfully refute the falsehood, we begin a seventh book also, quoting that saying of the prophet in prayer to God ‘Destroy them by thy truth’, obviously meaning by ‘them’ the doctrines opposed to the truth. For these are destroyed by God's truth, that after they have been destroyed those who have been set free from all distraction may say the words that follow—‘I will gladly sacrifice to thee’—and may offer a rational and smokeless sacrifice to the God of the universe.

2. It is Celsus' object to criticize the assertion that the history of Christ Jesus was prophesied by the prophets among the Jews. As a start we first examine his idea that those who teach the existence of another God beside the God of the Jews can make no reply at all to his difficulties, and that we, who have kept the same God, take refuge for our defence in the prophecies about Christ.