The following quote is from T. F. Torrance, he is discussing the term homoousion (of one substance), and its development within the early Christian Church. Notice the organic fluid nature that is being highlighted relative to this term’s function; I think something of significance is the underscoring of the relative importance of the term “homoousion” to the actual and Evangelical conceptuality that it captures. It is this language which served as the rallying cry from whence the early church took her trinitarian shape; in other words, homoousion was the culmination and symbol of an always and already assumption of the early Evangel—that Jesus and the Father (and the Holy Spirit) are of one substance (‘God of God’). I would encourage you to read this quote, it is quite long, but well worth your time!
In the Liber de Synodis, written in 359, Hilary tells us that he had already come to believe in the indivisible unity in being between the Son and the Father on the ground of what the Gospels and Epistles taught, before he even knew the word homoousion (or indeed had ever heard of the Nicene Creed), but it had greatly helped his belief. It is not the term itself that is significant but the central issue, the evangelical belief, which it was used to express. There is admittedly a danger in such expressions, for apart from the dubiousness of their history or their ambiguity, to make a single term carry such weight risks misunderstanding. “The infinite and boundless God cannot be made comprehensible by a few words of human speech.” If a brief expression like homoousios or consubstantialis is used, therefore, it must be interpreted with scrupulous care—and that is precisely what the Fathers undertook to do after the Council of Nicaea. Their primary intention was to preserve the heart and substance of the Gospel by providing safeguards for it against ‘the heretical rabble of the day’ and their gross misinterpretations. That is why the terms ousia and homoousios were used. Far from imposing an alien meaning upon the evangelical witness, theological language of this kind is adapted under the impact of divine revelation to convey themessage of the Gospel, so that in spite of the inadequacy of human language in itself it is made to indicate divine realities beyond its natural capacity and is to be understood in their light. That 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. This 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 coining, 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 interpretative 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 pregnant with intimations of still profounder aspects of divine reality in Jesus Christ pressing for realization in the mind of the Church. This is not to claim for the term homoousion that it is somehow sacrosanct and beyond reconsideration, for all theological terms and concepts fall short of the realities they intend. Like any other creative “definition” of this kind, owing to its essentially semantic function this also must be continually tested and revised in the light of what it was coined to express in the first place, as well as in the light of its fertility in the subsequent history of thought. (T. F. Torrance, ed., “The Incarnation: Ecumenical Studies in the Nicene-Constantinopolitan Creed: 381 A. D.,” xi–xiii)
How is that for one paragraph! What I really appreciate about Torrance’s synopsis is his “de-technicalization” of this theological terminology via placing it in its ministerial perspective. The consequence is such that homoousion is seen for what it is, an “instrumental” symbol used to provide precise communication of a whole slough of theologically freighted reality; namely the significance of the incarnation and its implications. It is this one word that seeks to “serve” the proclamation of the Gospel by recognizing the “touchstone” truth of the “Good News;” viz. that God assumed humanity. Without this reality, there is no people of God, because there is no reconciliation of people!