Although the essence does not contribute to the distinction, as if it were a part or member, the persons are not without it, or external to it; for the Father, if he were not God, could not be the Father; nor could the Son possibly be Son unless he were God. We say, then, that the Godhead is absolutely of itself. And hence also we hold that the Son, regarded as God, and without reference to person, is also of himself; though we also say that, regarded as Son, he is of the Father. Thus his essence is without beginning, while his person has its beginning in God.
