1 The earlier books of this treatise, written some time ago, contain, I think, an invincible proof that we hold and profess the faith in Father, Son, and Holy Spirit, which is taught by the Evangelists and Apostles, and that no commerce is possible between us and the heretics, inasmuch as they deny unconditionally, irrationally, and recklessly, the Divinity of our Lord Jesus Christ. Yet certain points remained which I have felt myself bound to include in this and the following books, in order to make our assurance of the faith even more certain by exposure of every one of their falsehoods and blasphemies. Accordingly, we will enquire first what are the dangers of their teaching, the risks involved by such irreverence; next, what principles they hold, and what arguments they advance against the apostolic faith to which we adhere, and by what sleight of language they impose upon the candour of their hearers; and lastly, by what method of comment they disarm the words of Scripture of their force and meaning.
Source: On the Trinity (New Advent)