1. In the three preceding books we have set out in detail the arguments that occurred to us in reply to Celsus* treatise; and now, holy Ambrose, after prayer to God through Christ we are undertaking a fourth book in reply to his next objections. May words be given to us, like those which are described in Jeremiah, where the Lord said to the prophet: ‘Behold, I have put my words in thy mouth as fire. Behold, I have this day set thee over nations and kingdoms, to root out and to destroy, to abolish and to pull down, to build up and to plant.’ For now we also need words to root out ideas contrary to the truth from every soul which has been distressed by Celsus' treatise or by opinions like his. And we also need ideas to destroy buildings of all false opinions and the arguments in Celsus' treatise which are like the building of those who said: ‘Come let us build ourselves a city and a tower, of which the top shall reach to heaven.’ Furthermore, we need wisdom to pull down every proud thought that exalts itself against the knowledge of God and Celsus' proud boasting which exalts itself against us.