According to Ayres’ analysis ( Augustine and the Trinity , 70), Augustine’s early explorations of the notion of the “inseparable action” of the Father, Son, and Spirit are expositions of what is standard Nicene orthodoxy: “First, Augustine sees Father, Son and Spirit as joined in a harmonic and inseparable unity that exhibits many of the features that we would normally attribute to a unifi ed agent (the paucity of evidence does not enable us to specify further the precise sort of unity Augustine envisages). Second, Augustine envisages this unity of action as an ordered unity initiated by the Father. The paradigmatic operation Augustine has in mind is that of creating, but Epistula 11 makes clear that the same unity of action is apparent in the work of salvation . . . . pro-Nicene accounts of inseparable operation frequently move beyond asserting merely that each of the divine three is involved in every act, by emphasizing the Father works through Son and in Spirit. Such assertions both emphasize the fact of Trinitarian order, and they begin to specify how we may conceive of the three as unified. Throughout his career, as we shall see, Augustine strongly emphasizes this ordered sequence, and his explorations of the doctrine may almost be read as a series of attempts to spell out how the
Father’s working through Son and in Spirit provides the key to understanding it.”

On this account, then, talk of “inseparable action” is not talk of “undifferentiated action” since for Augustine, and the Nicene tradition, “we must still follow Scripture and
accord each of the divine three a specific role (in some sense)” (90). The unified action of the Father, Son, and Spirit is unified by its initiation from the Father; its ordering and completion by Son and Spirit; and by the harmonization of the “roles” of each person.