St Gregory’s principal goal in Oration 31 is simple—to proclaim forthrightly the deity of the Holy Spirit. In his judgment it is no longer permissible for the Church to equivocate or to remain silent. The confession of the Holy Spirit is intrinsically joined to the Church’s confession of God as Holy Trinity:
For our part we have such confidence in the Godhead of the Spirit, that, rash though some may find it, we shall begin our theological exposition by applying identical expressions to the Three. “He was the true light that enlightens every man coming into the world”—yes, the Father. “He was the true light that enlightens every man coming into the world”—yes, the Son. “He was the true light that enlightens every man coming into the world—yes, the Comforter. These are three subjects and three verbs—he was and he was and he was. But a single reality was. There are three predicates—light and light and light. But the light is one, God is one. This is the meaning of David’s prophetic vision: “In your light we shall see light.” We receive the Son’s light from the Father’s light in the light of the Spirit: that is what we ourselves have seen and what we now proclaim. It is the plain and simple explanation of the Trinity. Let the treacherous deal treacherously, let the transgressor transgress—we shall preach what we know. We shall climb a lofty mountain and shout it out, if we are not given a hearing below. We shall extol the Spirit; we shall not be afraid. If we do have fear, it will be silence not of preaching. (31.4)
Christopher Beeley describes this compendious statement as “possibly the most complete and nuanced definition of the Trinity in all of patristic literature” (Gregory of Nazianzus on the Trinity and the Knowledge of God, p. 197). In it Gregory sets forth the trinitarian grammar of the Church: three bearers of a single reality; three predicates yet the same predicate. In this passage we encounter one of Nazianzen’s favorite biblical verses: “In your light we shall see light” (Ps 36:9). Note the critical position of the Spirit. By the light of the Spirit we are given to share in the light of the Father mediated to us in the light of the Son. The Spirit is the gift of the indwelling God. In the Spirit we participate in the being and life of the uncreated Creator. In the Spirit we are brought to a knowledge of the Father as manifested in the person and history of Jesus Christ. Beeley offers his interpretation of Gregory’s confession: “‘Theology’ is therefore the knowledge of the Trinity as it is revealed within the divine economy. When one comes to know God one enters into God’s own triune life, knowing the Divinity that comes from the Father in the face of Jesus Christ by the power of the Holy Spirit, who fully share that Divinity, as God come from God in God” (p. 197). This is not an abstract or theoretical knowledge but a personal knowing acquired through the experience of the Holy Trinity in the sacramental and ascetical life of the Church.
The confession of the Godhood of the Spirit, therefore, is not and cannot be an inconsequential matter for Gregory. To deny the divinity of the Spirit is to call into question the divine gift of theosis bestowed in the baptism of Christ (see “St Gregory Nazianzen and the Holy Spirit“). An incomplete deity is of no salvific use to us. If the Spirit is a creature, Gregory asks, “how can he make me God? How can he link me with deity?” (31.4). Two months earlier Gregory had displayed a fair amount of patience with the Pneumatomachians (see Oration 41); but the time for patience is over. Even the reverent silence of St Basil of Caesarea and his fellow “non-proclaimers” is no longer acceptable. The deity of the Spirit must be clearly and openly declared.
How then are we to understand the relationship between the Spirit and the Father? The Son is begotten by the Father. If the Spirit is also generated by the Father, the Eunomians asked, does that not mean that the Father has two sons? Are Jesus and the Spirit brothers? “Make them twins if you like,” Gregory acidly retorts, “or one older than the other, since you have a penchant for corporeal ideas” (31.7). The divine generations are spiritual, incorporeal, eternal, incomprehensible. Just as the Church uses a biblical term to speak of the Father’s generation of the Son, namely “beget” (the Father begets the Son), so Gregory proposes a biblical term to speak of the Father’s generation of the Spirit, namely, “proceed” (the Spirit proceeds from the Father). Thus the hypostatic distinctiveness of the Spirit is preserved. “Insofar as he proceeds from the Father,” Nazianzen explains, “he is no creature; inasmuch as he is not begotten, he is no Son; and to the extent that procession is the mean between ingeneracy and generacy, he is God” (31.8). The persons of the Trinity are distinguished precisely by—and only by—their mutual relationships (31.9). The Father is ingenerate, unbegotten, unoriginate. The Son is eternally begotten by the Father: he derives his existence from the Unbegotten Deity. The Spirit eternally proceeds from the Father: he derives his existence from the Uncaused God. As Gregory succinctly states in Oration 25: “The particular character of the Father is the ingeneracy, that of the Son is the generation, that of the Spirit is the procession” (25.16). In his farewell address Gregory spoke of the trinitarian relations in this way:
The One without beginning and the Beginning and the One who is with the Beginning are one God. Being without beginning is not the nature of the One without beginning, nor is being unbegotten; for nature is never a designation for what something is not, but for what something is. The affirmation of what is is not the denial of what is not. Nor is the Beginning kept separate from that which is without beginning by the fact that it is a Beginning: for being the Beginning is not his nature, any more than being the One without beginning is the nature of the other. These characteristics “surround” nature, but are not nature. And the One who is with the One without beginning and with the Beginning is not something else than what they are. The name of the One without beginning is “Father,” of the Beginning “Son,” of the One with the Beginning “Holy Spirit.” There is one nature for all three: God. (42.15)
Is it possible for mere humans to understand what we mean when we talk about the divine processions? Absolutely not. If we were to attempt to figure it out, we would surely go mad! (31.8).
The confession of the Spirit’s procession from the Father immediately raises the controversial question left open at the Council of Nicaea, Is the Holy Spirit consubstantial with the Father? Basil had avoided the employment of substance language when speaking of the Spirit; and the 381 Council of Constantinople followed Basil, not Gregory Nazianzen, on this point. For Basil, once one has identified the Spirit as uncreated, the profession of the homoousios of the Spirit becomes irrelevant and unnecessary (see John Zizioulas, Communion and Otherness, pp. 182-184). Substance language is too easily misinterpreted for modalist purposes. He preferred instead the word koinonia to speak of the unity of the divine persons: “But the Spirit is organically united with God, not because of the needs of each moment, but through communion in the divine nature” (On the Holy Spirit 13.20). In his Fifth Theological Oration, though, Gregory decisively breaks with his old friend (31.10). Is the Holy Spirit consubstantial? The Theologian boldly answers, “If he is God, yes!”