For over 2,000 years observant Jews have recited the Shema at daily prayers: “Hear, O Israel, the LORD is our God, the LORD is one” (Dt 6:4). To Israel was granted the revelation of the one God. Through Jesus of Nazareth, the Messiah of Israel, this revelation was bequeathed to the Church. The ecumenical Creed of Nicaea thus begins: “We believe in one God, the Father Almighty, Maker of all things visible and invisible.” But this same creed then goes on to confess belief in Jesus Christ and in the Holy Spirit. This raises the question, how are Jesus and the Spirit coordinated with the one God? Who precisely are they?
For the fourth century heretic Eunomius the answer is clear: the uncreated Deity radically transcends the world. The divine substance is eternal, simple, incomposite, immutable, incommunicable, indivisible; but most importantly, it is properly named unbegotten. God owes his existence to no other reality. “Unbegotten” is not just one of many negative terms; it is a privileged alpha-privative that precisely delineates the divine substance and thus gives us an exact knowledge of divinity. In his own mind Eunomius has fully embraced the biblical monotheism of Israel and refined it through careful philosophical reasoning. He believes that he is merely elaborating what it means for the God of the Christian faith to be the one God. This is not the deity of Plato, Aristotle, or Plotinus, each of which is eternally and necessarily related to the cosmos. This is the transcendent God of the Book of Genesis who creates beings in free exercise of divine will:
If we purify our notions of these matters with exactitude, we will understand that God’s mode of activity is not human but effortless and divine. We must not think that the [divine] activity is some kind of motion or division of his essence. This is in fact what those who have been led astray by pagan sophistries do have to suppose because they have united the activity to the essence and therefore present the world as coterminous with God. (Apol. 22)
Creation is an expression not of the divine essence but of the divine will. If the divine essence is involved in the creation of the world, Eunomius reasons, then the world must be eternal, and the Church will have embraced the errors of the Greeks:
We … do not consider it unhazardous to have to unite the action to the essence. We recognize that the divine essence is without beginning, simple, and endless, but we also recognize that its action is neither without beginning nor without ending. … There is no need, therefore, to accept the half-baked opinions of outsiders and unite the action to the essence. On the contrary, we must believe that the action which is the truest and most befitting God is his will and this will is sufficient to bring into existence and to redeem all things, as indeed the prophetic voice bears witness: “Whatever he willed to do, he did.” (Apol. 23)
The divine will, and everything it generates, must be located therefore outside of God—only thus is the freedom of God protected. There is a decisive difference between divine being and divine willing. Kahled Anatolios explains:
Eunomius’ insistence on the positive incomparability of the Unbegotten with respect to creation also entails a radical differentiation between divine being and divine willing. The being of the Unbegotten is absolutely prior and impervious to any process of causality, whereas divine willing is an activity in the order of causality and the term of such activity is always external and posterior to the divine essence. Moreover, Eunomius insists that divine willing, even considered from the perspective of divine agency, can never be eternal. If the divine agency were eternal, so would be the term of the activity of that agency. The logical end of such a chain of reasoning … would make the world coordinate with God (back to Origen!). It is crucial to see that, for Eunomius, the Unbegotten is not so much first cause or prime mover as utterly and self-sufficiently beyond all processes of causality, even with respect to the active agency of causality. God-acting-as-cause is, as it were, a secondary, temporary, and separable realm from God-as-Unbegotten; the latter is a description of the divine essence, while the former in no way implicates the essence. (Retrieving Nicaea, p. 74)
According to Eunomius all divine activity (energeia) is external to the divine substance (ousia) and therefore “coterminous not with the essence but with its product” (Anatolios, p. 74).
Where then does Christ Jesus and the Holy Spirit fit into this system? The gospels clearly teach that Jesus is from God and begotten by God. By Eunomian logic, Christ Jesus must therefore be a work of the divine will and thus extrinsic to the divine essence. If the generation of the Son were in some way internal to the Godhead, as the Nicene Creed asserts, then we would be back with the monism of Greek philosophy and the eternality of the cosmos. Thus the heresy was born that scandalized even many of the opponents of Nicaea: the Son (and a fortiori the Spirit) is dissimilar in being to the Father.