A friend pointed me to this remarkable statement from Augustine’s de doctrina Christiana. Augustine is distinguishing between uti and frui, use and enjoyment, emphasizing that the only thing that can be enjoyed in itself, rather than for the sake of something else, is God. He elaborates with a brief Trinitarian confession:
“The true objects of enjoyment, then, are the Father and the Son and the Holy Spirit, who are at the same time the Trinity, one Being, supreme above all, and common to all who enjoy Him, if He is an object, and not rather the cause of all objects, or indeed even if He is the cause of all. For it is not easy to find a name that will suitably express so great excellence, unless it is better to speak in this way: The Trinity, one God, of whom are all things, through whom are all things, in whom are all things. Thus the Father and the Son and the Holy Spirit, and each of these by Himself, is God, and at the same time they are all one God; and each of them by Himself is a complete substance, and yet they are all one substance. The Father is not the Son nor the Holy Spirit; the Son is not the Father nor the Holy Spirit; the Holy Spirit is not the Father nor the Son: but the Father is only Father, the Son is only Son, and the Holy Spirit is only Holy Spirit. To all three belong the same eternity, the same unchangeableness, the same majesty, the same power. In the Father is unity, in the Son equality, in the Holy Spirit the harmony of unity and equality; and these three are all one because of the Father, all equal because of the Son, and all harmonious because of the Holy Spirit” (1.4).
Much of this is unremarkable boilerplate confession of Trinity, but the final sentences are remarkable. Each person is unique; the Father is Father and nothing but Father, the Son nothing but Son, the Spirit only the Spirit. Each possess “the same” (eadem) eternity, unchangeableness, majesty, and power. And then this: “In Patre unitas, in Filio aequalitas, in Spiritu Sancto unitatis aequalitatisque concordia. Et tria haec unum omnia propter Patrem, aequalia omnia propter Filium, connexa omnia propter Spiritum Sanctum.”
Unity is associated with the Father, equality with the Son, concordia with the Spirit. Specifically, the concordia of the Spirit is the harmony between the unity that is the Father’s particular quality or gift and the equality that comes from the Son. The point is not that the Father is the locus of unity; Augustine is not saying that the Trinity is one God because everything originates from the Father. Or, he is not saying that explicitly. In some unspecified way, the unity of the three is propter Patrem. The three are all one because of the Father; unity is a quality of the whole Trinity, a reality rooted in or gifted by the Father. But unity is not the only thing Augustine is concerned about. It is equally important that the three Persons are equal (assuming the tria haec is implicit in the second and third phrase, tria haec unum . . . aequalia . . . connexa). And the equality is not from the Father, but propter Filium; equality is somehow a gift or result of the Son. And the harmony of the unity that comes from the Father and the equality that exists on account of the Son, perhaps even the harmony of Father and Son as such, is a gift of the Spirit, propter Spiritum Sanctum.
It’s not clear where Augustine gets these designations and associations. My interest is less in the specifics than in the logic of the statement, namely, that each of the Persons is a source of a unique quality that is shared by all three, or a quality that is a quality of the whole Trinity. This is not a unidirectional conception, as if everything flows downhill from Father to Son to Spirit. Rather, unity, equality, and harmony flow out from the Persons, and spread over the whole Triune being.
That may or may not prove correct, but it is a rare thought and worthy of serious consideration.