On the Holy Trinity 74Whatever is Spoken of God According to Substance, is Spoken of Each Person Severally, and Together of the Trinity Itself. One Essence in God, and Three, in Greek, Hypostases, in Latin, Persons.

9. Wherefore let us hold this above all, that whatsoever is said of that most eminent and divine loftiness in respect to itself, is said in respect to substance, but that which is said in relation to anything, is not said in respect to substance, but relatively; and that the effect of the same substance in Father and Son and Holy Spirit is, that whatsoever is said of each in respect to themselves, is to be taken of them, not in the plural in sum, but in the singular. For as the Father is God, and the Son is God, and the Holy Spirit is God, which no one doubts to be said in respect to substance, yet we do not say that the very Supreme Trinity itself is three Gods, but one God. So the Father is great, the Son great, and the Holy Spirit great; yet not three greats, but one great. For it is not written of the Father alone, as they perversely suppose, but of the Father and the Son and the Holy Spirit, "Thou art great: Thou art God alone." And the Father is good, the Son good, and the Holy Spirit good; yet not three goods, but one good, of whom it is said, "None is good, save one, that is, God." For the Lord Jesus, lest He should be understood as man only by him who said, "Good Master," as addressing a man, does not therefore say, There is none good, save the Father alone; but, "None is good, save one, that is, God." For the Father by Himself is declared by the name of Father; but by the name of God, both Himself and the Son and the Holy Spirit, because the Trinity is one God. But position, and condition, and places, and times, are not said to be in God properly, but metaphorically and through similitudes. For He is both said to dwell between the cherubims, which is spoken in respect to position; and to be covered with the deep as with a garment, which is said in respect to condition; and "Thy years shall have no end," which is said in respect of time; and, "If I ascend up into heaven, Thou art there," which is said in respect to place. And as respects action (or making), perhaps it may be said most truly of God alone, for God alone makes and Himself is not made. Nor is He liable to passions as far as belongs to that substance whereby He is God. So the Father is omnipotent, the Son omnipotent, and the Holy Spirit is omnipotent; yet not three omnipotents, but one omnipotent: "For of Him are all things, and through Him are all things, and in Him are all things; to whom be glory." Whatever, therefore, is spoken of God in respect to Himself, is both spoken singly of each person, that is, of the Father, and the Son, and the Holy Spirit; and together of the Trinity itself, not plurally but in the singular. For inasmuch as to God it is not one thing to be, and another thing to be great, but to Him it is the same thing to be, as it is to be great; therefore, as we do not say three essences, so we do not say three greatnesses, but one essence and one greatness. I say essence, which in Greek is called ousia, and which we call more usually substance.

10. They indeed use also the word hypostasis; but they intend to put a difference, I know not what, between ousia and hypostasis: so that most of ourselves who treat these things in the Greek language, are accustomed to say, mian ousian, treis upostaseis or in Latin, one essence, three substances.