Expositio super symbolum Nicenum

And born of the Father before all ages.

In this name, moreover, three things are implied, three are understood: the spirituality of the nativity, because he was born of the Father in an ineffable manner; and the identity of nature, because consubstantial with the Father; and the singularity of the nativity, because he alone was born of the Father — and thus, born of the Father.

Before all ages.

Here his coeternity is implied, which is against those who deny that he is eternal. For this circumlocution, "before all ages," designates eternity. And note that this preposition "from" (ex) in sacred scripture sometimes denotes material cause, as when it is said that all things were created from the four elements; sometimes authority; sometimes efficient cause, as when it is said that all things have their existence from God; sometimes it denotes, as it were, formal cause, as when it is said: God saves out of mercy; sometimes the origin of a nativity, as here, and born of the Father.