One of the main principles the Church Fathers used to establish the doctrine of the Trinity was to recognize that a unity of activities or “operations” between the persons meant a unity of being and identity. Early in the 4th Century theologians like Athanasius argued from this principle to establish the divinity and consubstantiality of the Son with the Father. If the Son is the agent of creation and salvation, then he shares this work with the Father. In which case, he must also share the same simple, indivisible nature with him. (And just as a side-note, this isn’t abstract logic-chopping, but the sort of reasoning Scripture points us to all over the place, but see especially 1 Corinthians 12:1-12, or Ephesians 1).
Of course, one of the nice things about having to hammer out those principles for thinking about the Son was that they were then close at hand when conflict about the Holy Spirit arose later in the 4th Century. It’s just that sort of argument that Basil of Caesarea appeals to in his masterful treatise On the Holy Spirit. In it he’s arguing against the Macedonians (also known as Pneumatomachians, or “Spirit-fighters”) who, for all sorts of reasons, held that the Holy Spirit shouldn’t be ranked with the Father and the Son.
Against them, Basil levels a broad array of penetrating exegetical and theological arguments . But towards the center of the work, in chapter 16, he sets out to establish that “the Holy Spirit is indivisible and inseparable from the Father and the Son” by appealing to their inseparable operations. He traces the unity of their work in the work of prophecy and inspiration, creation, and even the final judgment of the Son. Probably my favorite section in the chapter (and maybe the whole book) comes in his description of the Spirit’s work in the Son’s ministry:
But when we speak of the plan of salvation for men, accomplished in God’s goodness by our great God and Savior Jesus Christ, who would deny that it was all made possible through the grace of the Spirit?
Whether you wish to examine the Old Testament – the blessings of the patriarchs, the help given through the law, the types, the prophecies, the victories in battle, the miracles performed through righteous men – or everything that happened since the Lord’s coming in the flesh, it all comes to pass through the Spirit.
In the first place, the Lord was anointed with the Holy Spirit, who would henceforth be inseparably united to His very flesh, as it is written, “He on whom you see the Spirit descend and remain, this is He who … is my beloved Son,” and “God anointed Jesus of Nazareth with the Holy Spirit.”
After His baptism, the Holy Spirit was present in every action He performed. He was there when the Lord was tempted by the devil: “Jesus was led up by the Spirit into the wilderness to be tempted.” The Spirit was united with Jesus when He performed miracles: “But if it is by the Spirit of God that I cast out demons … ”
Nor did the Spirit leave Him after His resurrection from the dead. When the Lord renewed mankind by breathing into His Apostles’ faces, (thus restoring the grace which Adam had lost, which God breathed into him in the beginning) what did He say? “Receive the Holy Spirit. If you forgive the sins of any, they are forgiven; if you retain the sins of any, they are retained.”
Is it not indisputably clear that the Church is set in order by the Holy Spirit? “God has appointed in the Church first apostles, second prophets, third teachers, then workers of miracles, then healers, helpers, administrators, speakers in various kinds of tongues.” This order is established according to the different gifts distributed by the Spirit. (On the Holy Spirit, 16.39)
There’s much to comment on here, but I’ll keep my remarks brief.
First, see how he begins his discussion of the Spirit’s work in plan of salvation accomplished by God in Jesus Christ: the Old Testament. For Basil, the economy of salvation begins in the book of Genesis, not the Gospel of Matthew. He sees all of it–the Law, the prophets, and even Israel’s victories in battle–under the aegis of the Spirit.
Second, there’s a bit of what we might call a “Spirit-Christology” (but not an overwhelming one), that sees the Son’s work in the Incarnation as irrefragably bound up with the agency of the Spirit. You simply cannot explain Jesus’ ministry without the work of the Spirit–as the Spirit’s anointing was “in his flesh”, “the Holy Spirit was present in every action He performed.” He actually does a lot with this throughout the treatise as a whole, but the point here is, with their agency so tightly bound up, how can you even think of dividing the being of the Spirit from the Son (and therefore the Father)? (Incidentally, he shares this emphasis with Irenaeus of Lyon, if you want to do more digging in the Fathers).
Third, even though he’s going to turn to the final things in the next section, Basil chooses to end this segment on the economy of salvation with the establishment of the Church. Pouring out the gifts that create the Church is obviously a divine act of the Son and the Father. And so if the Spirit is seen as the one who distributes those gifts, this is only because he shares the divine glory and being of Father and Son.
It is for these reasons Basil is quite right to insist that offer glory “to the Father, with the Son together with the Holy Spirit.”
Soli Deo Gloria