Gaius Marius Victorinus

It was the incarnate Word who accomplished the mystery of our salvation. It was he who freed us and redeemed us. We believe in him who is our Savior through the cross and through his resurrection from the dead.

Therefore God is also Being, both existing and substance, although he is above all that because he is the Father of all. We should not be afraid to use the word substance of God, because when words are lacking to describe the highest realities, it is not inappropriate for us to take terms borrowed from what we do know and understand and use them in this special sense.