The doctrine of the vicarious humanity of Jesus Christ is of the highest import for us Evangelical Calvinists. We see, following Torrance and Barth, this doctrine providing a foundational reality for thinking about theological ontology, epistemology, soteriology, ecclesiology etc. This focus reorientates the way we think about salvation in the sense that we start from the premise that salvation must start with a doctrine of God and ‘work its way down from there’ (think of incarnation). As we think this alongside Barth what stands out is an emphasis on God’s humanity; that is, an emphasis on the idea that without God freely choosing to not be God without us that there would be no gracious basis or space wherein salvation could obtain. We think this approach avoids the problematic that often attends the Augustinian emphasis of salvation as that is thought from below; as illustrated by Augustine’s doctrine of predestination (i.e. that God chooses particular individual humans to be saved in contrast to the Barth understanding wherein salvation is first grounded in the union of God and humanity in the hypostatic union realized in the person of Jesus Christ; thus all humanity is represented in the salvation event just as the humanity Christ assumes before the foundation of the world is a catholic humanity of the sort that all of humanity came to be in the first Adam in the original creation).
To help us appreciate what I am referring to let me refer to David Congdon (I’m reading his big book on Bultmann off and on) as he details how the humanity of Christ functions in the theology of Barth. We pick up with Congdon as he is comparing and contrasting Barth’s Christology with Bultmann’s; we won’t concern ourselves with the comparison so much, and instead focus on the good description that Congdon provides for us in regard to Barth’s understanding on the primacy of the humanity of Jesus Christ.
While we have isolated those aspects of Barth’s later work that highlight the conflict between him and Bultmann, we should not fail to note that, seen from another perspective, the theology in the fourth volume of Kirchliche Dogmatik draws nearer to Bultmann. This is because, compared to the period of dogmatic dissonance (1929–1939), the mature Barth unites deity and humanity in a way that permits, even requires, him to make the question of anthropology and human existence internal to the nature of theology, hence the humanity of God. The fruit of this is seen most clearly in KD 4.3, especially §71, where Barth develops his account of human vocation as something that “concerns us personally and affects us ‘existentially.’” But the human existentiality included within the divine existentiality is of a very particular sort, namely, it is the existence of the human Jesus (primary humanity) in distinction from all other human beings (secondary humanity). Beginning with his lecture on “Evangelische Theologiae im 19. Jahrhundert” on January 8, 1957, Barth defines his position as “theanthropology,” which he would later set over against what he calls “anthropotheology,” a term that replaces “natural theology” as the umbrella category for all the various theologies—from Schleiermacher to Bultmann, from pietism to mysticism, from the analogia entis to existentialism—that, in his judgment, talk about God by first talking about the creature. Theanthropology lets the particular humanity of Christ define what counts as genuinely human, whereas anthropotheology concerns itself with human presuppositions and conditions apart from and anterior to the Christ-event.
There are a variety of loci and implications to what Congdon is developing here, but what I want to highlight is the aspect that has to do with the primary humanity of Jesus Christ and Barth’s Theanthropology.
For Evangelical Calvinists the doctrine of the primacy of Jesus Christ reigns supreme. We believe that all of creation is oriented to and from the reality of God’s choice to pre-temporally be for us in his choice to not be God without us in the incarnation. As such we see the teleology of creation (or its purpose) ultimately grounded in the joy that the Father has in his Son in the bond and fellowship of love they share one with the other, one in the other by the Holy Spirit (that is pretty trad right there). Following along with the Apostle Paul’s creational themes in Romans 8 (as he riffs on Genesis) and Colossians 1, there is a primacy to humanity vis-à-vis creation in general just as humanity is grounded in the reality of God’s life ‘to be human’ in the Son. That is the stewardship human beings have been given ‘over’ creation is only a mirroring and actualization of God’s reign over all of creation as that is realized in the effulgence of the Son’s eternal relation of the Father to the Son. In other words, creation’s inner-reality is grounded in God’s choice to be for the creation in the Son; as such creation’s orientation has always already been a teleology that has order and intelligibility insofar as that reality is realized in its magnification of the Son of God; insofar as the crowning reality of the creation has always already been grounded in the Kingly humanity of the Son; a humanity that is the point of creation to begin with—that God might share his Fatherly love, that he has always shared with the Son, by creating a world wherein counter-parts, individuated human creatures could participate by grace in the divine nature, and en-joy the fellowship and beauty that the Son and the Father by the Holy Spirit have always and eternally shared one with and in the other as the One True and Living Almighty God.
Along with Barth we want to see a Dogmatic primacy to the humanity of Christ; we want to see his humanity as archetypal of what it ultimately and redemptively means to be humanity as new creatures. We don’t want to attempt to grasp the humanity of God from our humanity as if our humanity comes prior to or in simultaneous relation with the humanity of God. No, we want to recognize that if there is going to be a meaningful and genuinely Christ-ian understanding of what it means to be a human we will not see that from our experiences as humans, but realize that, both protologically and eschatologically in and from the humanity that God has decided on as the norm of what it means for humans to be in relation with himself. We will think of humanity as if it is grounded in the eikon of God, in the imago Dei who is Jesus Christ (cf. Col. 1.15), and we will understand our humanity as it is recreated in the imago Christi as we then serve as images of the image of God in this world and bear witness to all of creation what its purpose is before God.
As we closed off with Congdon we see him referring to Barth’s reference of anthropotheology as a reference to all modes of theological reasoning that start with an anterior humanity that is thought of in abstraction from God’s Self-revelation in Jesus Christ (from a prior ‘above’); in abstraction from what it means to be human from a God-given orientation. We could add into the list that Barth thinks this label umbrellas, Augustinianism, at least in regard to Augustine’s doctrine of predestination and its from below soteriological orientation. It is an interesting mix to include someone like Schleiermacher and Augustine when thinking a doctrine of salvation, but probably not too far off (indeed Schleiermacher himself is quite Augustinian in certain important ways).
 David W. Congdon, The Mission of Demythologizing: Rudolf Bultmann’s Dialectical Theology (Minneapolis: Fortress Press, 2015), 212-13.