The One Christ: St. Augustine's Theology of Deification
144 The Holy Spirit's Indwelling soul is glued on behind him (Ps. 63:8). And for us it is good to cling to God (Ps. 73:27). . . .22
Unity, holiness, and charity are clearly seen as the essential predicates of the Spirit's nature and his relationship to both the Father and to the Son. We must not think that these attributes are not able to be predicated also of the Father and of the Son; they nonetheless belong particularly to the Holy Spirit because he is their communion, their love, and their sanctity. Perhaps sensing this danger, Augustine is careful to clarify that the Father and Son are also one, love, and holy not by participation but in their very own being. As soon as this consubstantiality is established, the Holy Spirit is again brought in as gift so as to show how the Father and the Son are one, love, and holiness. This is not to violate the principle laid down earlier (that all substance terms can be predicated equally of each of the divine persons), but to show that the nature of the gift is also the nature of the Father and the Son. Each person is divine and each is thus unity, holiness, and love not by participation [non participatione] but each in his very own being [sed essentia].
As soon as this piece of trinitarian theology is settled, Augustine turns to his audience and bids them to imitate God in such "mutuality" (Hill takes the opening Quod here as referring back to the unity and the bond of peace at Eph. 4:30). Such an imitation is not the necessary imitation of the Logos necessarily performed by all of creation which we examined back in chapter 1, but is now a free imitation of God which
22. Trin. 6.5.7; Hill, Trinity, 209: "Siue enim sit unitas amborum siue sanctitas siue caritas, siue ideo unitas quia caritas et ideo caritas, quia sanctitas, manifestum est quod non aliquis duorum est quo uterque coniungitur, quo genitus a gigente diligatur generatoremque summ diligat, sintque non participatione sed essentia sua neque dono superioris alicuius sed suo proprio seruantes unitatem spiritus in uinculo pacis. Quod imitari per gratiam et ad deum et ad nos ipsos iubemur . . . quia ipsius munere inter nos unum; cum illo autem unus spiritus quia agglutinatur anima nostra post eum. Et nobis haerere deo bonum est"; CCL 50.235.