And in one Lord Jesus Christ, the only-begotten Son of God, begotten of the Father before all worlds; God of God, Light of Light, very God of very God; begotten, not made, being of one substance with the Father, by whom all things were made.
One often runs into the complaint that the homoousion of Nicaea is a bit of philosophy imposed upon the biblical revelation. I would argue the exact opposite. The recognition of the oneness of being and agency of the Father and the Son was nothing less than a divinely inspired and definitive insight into the identity of Jesus Christ and his eternal relationship with God. Imagine if you will a group of mathematicians struggling over a specific problem, the blackboard filled with numbers and symbols, yet unable to figure out that one piece of “code” needed to make the equation work. And then suddenly, in a brilliant moment of revelation, one of them “sees” that which is missing and needed—and it all makes sense. The equation is complete. This, I think, is something like what happened in the fourth century with the conciliar confession of the homoousion. The Fathers of Nicaea may not have completely understood the decisive significance of this little word for their understanding of Christ; yet with the subsequent preaching, reflection, and clarification of Athanasius, Hilary of Poitiers, Basil of Caesarea, Gregory of Nazianzus, and Gregory of Nyssa, the Church eventually realized that a cognitive and noetic breakthrough had occurred. Thus St Athanasius would look back upon the 325 council and exclaim, “The Word of the Lord which came through the Ecumenical Synod at Nicaea, abides for ever” (Ad Afr. 1f). Thomas F. Torrance elaborates:
This is how we are to regard the term homoousion in the Creed, which has been reforged or reminted through the believing and doxological commitment of the Church to God’s self-revelation in Jesus Christ and harnessed by the Gospel to convey the all-important relation between the Son and the Father in a precise sense. That is to say, homoousion is in the first place an exegetical and clarificatory expression, having to do with the semantic relation between the sign and the reality signified, but in view of the act of discovery (which like all creative advances is irreversible) that lay behind it and was assisted through its coming, homoousion took on the role of an interpretative frame through which general understanding of the evangelical and apostolic witness was given more exact guidance throughout the Church. What the homoousion did was to give expression to the ontological substructure upon which the meaning of various biblical texts rested and through which they were integrated. As such it proved to be one of those movements of thought from a preconceptual to a conceptual act of understanding which the committed mind takes under the compelling demands of the reality into which it inquires, in this instance, the truth as it is in Jesus Christ. Far from being a rigid and alien imposition upon the Gospel, the homoousion has proved, through its bearing upon the ontic nexus in the relation of Christ to God the Father, to be so fertile as an interpretive instrument serving the Gospel in its continuing disclosure of ever deeper truth, that it was honoured in the Early Church as an “inspired” insight granted to the Nicene Fathers. Thus even the term expressing this insight justified itself in Ecumenical Council after Ecumenical Council because of its generative and heuristic power, for it was so well rooted in the source of the Church’s faith that it was pregnant with intimations of still profounder aspects of divine reality in Jesus Christ pressing for realization in the mind of the Church. (“Introduction” to The Incarnation, pp. xii-xiii)
The gospel of Jesus Christ rests upon the confession of the identity of being and agency between the Father and the Son. This is why the homoousion is dogma. It provides that framework apart from which the Holy Scriptures cannot be understood and apart from which the preaching and life of the Church ultimately makes no sense. In the words of Archbishop Methodios Fouyas: “We declare that neither Christianity without the incarnation nor the Creed without the homoousion is acceptable to us. The first constitutes the essence of our Faith. Christianity without the incarnation of God is meaningless and useless. Christ without being homoousios to the Father is neither the Revelation of God nor our Redeemer” (Incarnation, p. 11).