When you read Richard Muller back in 1983 on immutability and incarnation he sounds like Thomas Torrance and Karl Barth in significant ways. Obviously there are important differences as far as the modes of theological appropriation—in regard to the periods of theological development within which Muller is drawing versus Torrance/Barth—but what is shared is a common orthodoxy vis-à-vis the Chalcedonian tradition in its principle parts. Here is Muller followed by two quotes; one from Torrance the other from Barth:

Torrance,

think of the economic Trinity as the freely predetermined manifestation in the history of salvation of the eternal Trinity which God himself was before the foundation of the world, and eternally is. Hence, when we rightly speak of the oneness between the ontological Trinity and the economic Trinity, we may not speak of that oneness without distinguishing and delimiting it from the ontological Trinity—there are in any case . . . elements in the incarnate economy such as the time patter of human life in this world which we may not read back into the eternal Life of God. (Christian Doctrine of God, p. 109)[1]

Barth,

it is not just good sense but absolutely essential that along with all older theology we make a deliberate and sharp distinction between the Trinity of God as we may know it in the Word of God revealed, written and proclaimed, and God’s immanent Trinity, i.e., between “God in Himself” and “God for us,” between the “eternal history of God” and His temporal acts. . . . “God for us” does not arise as a matter of course out of the “God in Himself.” . . . It is true as an act of God, as a step which God takes towards man. (CD I/1, p. 72)[2]

Clearly, where Muller ends up going, theologically, and where Barth/Torrance arrive are substantially different in particular ways. But I thought it was at least worth highlighting that Barth/Torrance and Muller, at least in regard to some basic commitments relative to Christology share a common desire to work in and from the Chalcedonian patterning of the ecumenical church. Of course, this is not uncontroversial, particularly when it comes to the way Barth is read based upon his actualistic “metaphysic” or “postmetaphysic” as the case might be. Paul Molnar argues, almost exhaustively, that Barth ought to be read traditionally; this in contrast to the Bruce McCormack camp that sees shift in Barth’s Christological fathoming between his Church Dogmatics I/1 and IV/1 based upon his reformulation of election in II/1. But that’s a story for another day.

*Richard Muller quotes: from this essay.

[1] Cited by Paul D. Molnar, Faith, Freedom and the Spirit: The Economic Trinity in Barth, Torrance and Contemporary Theology (Downers Grove, Illinois: IVP Academic, 2015), 348.

[2] Ibid.