5 In the earlier books, then, while maintaining the profession of a faith, I trust, sincere, and a truth uncorrupted, we arranged the method of our answer throughout, so that (though such are our limitations, that human language can never be safe from exception) no one could contradict us without an open profession of godlessness. For so completely have we demonstrated the true meaning of those texts which they cunningly filch from the Gospels and appropriate for their own teaching, that if any one denies it, he cannot escape on the plea of ignorance, but is condemned out of his own mouth of godlessness.
Further, we have, according to the gift of the Holy Ghost, so cautiously proceeded throughout in our proof of the faith, that no charge could possibly be trumped up against us. For it is their way to fill the ears of the unwary with declarations that we deny the birth of Christ, when we preach the unity of the Godhead; and they say that by the text, I and the Father are one, we confess that God is solitary: thus, according to them, we say that the Unbegotten God descended into the Virgin, and was born man, and that He refers the opening word 'I' to the dispensation of His flesh, but adds to it the proof of His divinity, And the Father, as being the Father of Himself as man; and further, that, consisting of two Persons, human and divine, He said of Himself, We are one.
Source: On the Trinity (New Advent)