The One Christ: St. Augustine's Theology of Deification
148 The Holy Spirit's Indwelling
Son, is a provocative way to display Augustine's contribution to trinitarian thought. The early church was, to a large extent, bedeviled by two tendencies inimical to the creedal formulation of the consubstantiality of the three divine persons.
The first was the early focus on the equality of the Father and the Son to the apparent exclusion (or at least minimal treatment) of the Holy Spirit. Prior to the Cappadocians, many treatises on the Trinity failed to develop a clear trihypostatic theology, tending to focus on the perfect identity involved in the eternal begetting of the Son and the Son's consequent equality with the Father, thus inclined not to grant so much detailed attention to the Holy Spirit.29 Augustine was aware of this problem and attempted to save the churchmen he had read by offering a helpful hermeneutic. In a sermon delivered in 418 A.D., he admits that just because the Holy Spirit is not mentioned in theological treatises regarding the equality of the Father and the Son does not necessarily mean that he has been overlooked. Why not? The Bishop preaches that the silence surrounding the Spirit in much of theological speculation actually shows how he is named in the dual signification of the Father and of the Son because only he is uniquely understood as being equally both of theirs: "He is not the Spirit only of the Father, or only of the Son, but he is the Spirit of the Father and of the Son. So when he's not mentioned, and they are both named, he is understood in them, because he is both of theirs."30
29. This is not to cast doctrinal suspicion on these earlier trinitarian treatises, but simply to point out that the attention given over to the homoousios of the Spirit pales in comparison to the Son's equality to the Father. Take Novatian, for example, who does not even "expressly give the Holy Spirit the name of God" (Russell DeSimone, trans., Novatian: The Writings [Washington, D.C.: Catholic University of America Press, 1974], 17); moreover, Novatian's De Trinitate dedicates merely one chapter (§29) explicitly to the Spirit (see also J. N. D. Kelly, Early Christian Writings [London: Adam & Charles Black, 1965 [3rd ed], 126, where he calls Novatian's doctrine of the Spirit "rudimentary," pointing out that "he makes no mention of His subsistence as a Person.").
30. s. 217.2; Hill, Sermons (III/6), 178: "Non, quia tacitus est, praetermissus est spiritus sanctus"; PLS 2.663; see also note 57 below.