Often it is tempting, at least in the Reformed tradition, to think that Christ’s office as mediator between God and humanity (1 Tim. 2:5) began with his incarnation. This, in turn, stems from the idea that Christ’s mediatorial work is exclusively soteriological; that is, our need for a mediator is strictly tied to our need for reconciliation. If so, then theoretically, had we as the human race never fallen into sin, then Christ would never have undertaken a mediatorial role on our behalf. Interestingly, however, this is very different from than conception that one of the esteemed fathers of the Reformed faith, John Calvin, expressed about Christ’s mediation. Julie Canlis clearly brings out this point in her book Calvin’s Ladder when she writes:
Calvin’s definition of mediation has a much broader range than that to which we are normally accustomed … Calvin is quite clear that Christ’s mediation did not originate with sin “but from the beginning of creation he already truly was mediator, for he always was the head of the Church, had primacy over the angels, and was the firstborn of every creature.” … Refusing to collapse mediation into expiation, Calvin held the two together (the Mediator should now always be seen “together with his sacrifice”) while still preserving the initial sense of the Mediator as sustainer of creation. For it was only “man’s rebellion that brought it about that expiation was necessary to
reconcile us to God.” Here we see Calvin’s relentless theocentrism at work, where he will allow neither human endowment nor human sin to be the starting gun for the marathon of the human race. It is God and his intent that has the first and last say: “It is the proper function of the mediator to unite us to God.” In this grand sweep, Calvin is positioning the forthcoming redemption (mediation-expiation) of Christ within a more comprehensive story, that of the God who intends us for communion (mediation-union)…
Although this doctrine of Christ’s eternal mediation is not without its pitfalls, its purpose is to build communion into the structure of things. In his doctrine of creation, Calvin refuses to envision a general relationship between the triune God and humanity. “What comparison is there between a creature and the Creator, without the interposition of a Mediator?” All creation is related to God in the second person of the Trinity, who mediates creation and its telos. All things are created by him, created to exist in him, and created for perfect union with him (“as much as their capacity will allow”). This arrangement is not due to sin, but to the en Christo way that God relates to humanity. He has not structured a universe in which life, grace, and “benefits” can be had apart from him …
Even in the Garden of Eden, Adam received life not from God simpliciter but from Christ. “He was the mid-point between God and creatures, so that the life which was otherwise hidden in God would flow from him.” Not only did life flow from him, but Adam’s life was in him. “Previously, direct communication with God was the source of life to Adam; but, from the moment in which he became alienated from God, it was necessary that he should recover life by the death of Christ, by whose life he then lived.” Calvin makes a general point that human life is maintained only by participation in God but then he more pointedly embeds this in the Mediator. Perhaps Calvin’s greatest contribution to a theology of creation is the relentless insistence and clarity with which he views humanity’s relationship with the Mediator: we do not have an “in” to God, except through Christ.
This is both fascinating and instructive. According to Canlis, Calvin understood the mediatorial role of Christ as including but not limited to his expiatory and reconciling work. For Calvin, Christ was mediator between God and humanity prior to his incarnation, extending back before the foundation of the world and to the very beginning of time as the one through whom and for whom all things were created. This, I think, is what Paul was intending when he wrote in Colossians 1 that Christ is not only the “firstborn from the dead” but also the “firstborn of all creation”! That is, the One who reconciled humanity to God is the same One who brought humanity into being in the first place and who continues to sustain humanity with the word of his power. In other words, Christ has eternally been mediator, and there was never a time, even before our fall into sin, in which we as human beings could live in communion with God apart from a relation mediated exclusively through Christ.
If we begin to grasp this phenomenal truth, we will also begin to grasp the enormous impact that it has on virtually ever aspect of our faith, not least of which is our approaching to interpreting Scripture and doing theology. Calvin himself explained that:
This is the whole of what we should seek in the Scriptures: to be well acquainted with JESUS CHRIST, and the Infinite Riches which are comprised in Him; and which are, by Him, offered to us from GOD His Father. For if the Law and the Prophets be most carefully searched, there is not to be found in them one word which does not refer and lead to Him. And in fact, since all the treasures of Wisdom and Knowledge are hid in Him, it is not well to have any other end or object; unless we wish, as with deliberate intention, to turn ourselves away from the light of Truth, to go astray into the thick darkness of Falsehood…. It is not then allowable that we turn ourselves away and wander here and there, however little it may be; but our understanding must be altogether stayed at this point, to learn in the Scriptures to know only JESUS CHRIST, in order to be, by Him, conducted straight to the FATHER, who contains within Himself all Perfection.
Since Christ has eternally been the mediator between God and humanity, this means that all divine revelation, even prior to the incarnation, came exclusively by and for Jesus Christ. Following from this, as Calvin stresses, we must recognize that the purpose of all Scripture, and not simply of the New Testament, is to bear witness to Jesus Christ. Better still: Christ’s purpose in mediating revelation, the record of which we have in both Old and New Testaments, was to bear witness to himself. Therefore, unless we seek to know Christ, and only Christ, in all of Scripture, then we have missed the point entirely, regardless of how finely-honed our historical, grammatical, or critical methods of interpretation may be. As Jesus himself criticized his contemporaries: “You search the Scriptures because you think that in them you have eternal life; and it is they that bear witness about me” (John 5:39).
This is to say that our approach to reading Scripture and drawing theological conclusions must be relentlessly Christocentric – Christocentric in a principial sense (perhaps in a way that even goes beyond Calvin) that looks to Christ as the beginning, the end, the sum and the standard from which everything must proceed, to which everything must arrive, and by which everything must be judged. The particular importance of the eternal mediation of Christ is that it grounds this principial-Christocentric hermeneutic in ontology rather than merely in epistemology. That is to say, the necessity of a principial-Christocentric hermeneutic (which, to repeat, sees Christ as the sum and substance of all Scripture and theology) is the result of the way things actually are – i.e. the principial-Christocentric nature of all reality – and not simply a kind of pragmatic “best practice” that enables us to better comprehend the intended meaning of the canonical texts. Understood this way, a principial-Christocentric approach to Scripture and theology becomes a matter of obedience; it is the responsibility laid upon us by the objective fact that Christ himself has always been and will always be the one mediator between God and humanity; he is the one Word of God, the one through whom and for whom all things were created and in whom all things are reconciled.
There is much more that could be said here, not least in relation to the impact that this has on doctrines such as election (if Christ is “the starting gun for the marathon of the human race”, then what relation does this establish between the election of Christ and the election of humanity?) and atonement (if the mediator who reconciles humanity is identical to the mediator who created humanity, then what impact does this have on the scope of Christ’s saving work?). However, it is sufficient simply to conclude by reiterating that if we come to terms with the full ramifications of the eternal mediation of Christ, then nothing can remain unchanged.
 Julie Canlis. Calvin’s Ladder: A Spiritual Theology of Ascent and Ascension (Grand Rapids: Eerdmans, 2010), Kindle Edition, Locations 600-647. Seen Canlis for bibliographic data of sources that she cites.
 John Calvin, Christ the End of the Law: Being the Preface to the Geneva Bible of 1550, (London: William Tegg, & Co., 1850), pp.31-33.