Barth on (let's say) the simple substitution of Creator-Redeemer-Sustainer

"The content of the doctrine of the Trinity which the Church has formulated and dogmatics has to repeat and Church proclamation respect is not that God in His relation to man is Creator, Mediator and Redeemer, but that God in Himself is eternally God the Father, Son and Holy Spirit. . . . God Himself cannot be dissolved [nicht aufgeht] into His work and activity [for us]. . . ."

     Karl Barth, CD I/2, pp. 878-879, as quoted by George Hunsinger, in his "Election and the Trinity:  twenty-five theses on the theology of Karl Barth," Modern theology 24, no. 2 (April 2008):  189, but with the Thomson/Knight translation restored (since Hunsinger, or perhaps just Modern theology, drops an ellipsis).

The stress in context is on "revelation," [1] that "work and activity of God in His revelation" from which is derived the both [2b] the doctrine of God as "in His revelation . . . Creator, Mediator and Redeemer" and [2a] the logically prior and much more foundational doctrine of God as "in Himself and to all eternity . . . Father, Son and Holy Spirit."  [1] "The work and activity" of revelation is therefore the "organising and controlling centre of dogmatics" out of which [2] doctrine arises, and in particular [2a] "the doctrine of the Trinity . . . as part of [2b] "the doctrine of God [as Creator, Mediator and Redeemer], which cannot be exhausted in [2a] the doctrine of the Trinity," and stands with it "alongside [3] the doctrines of creation, atonement and redemption."  We need [2b] because "the impression can and must be destroyed that at every point [(I might have said level)] we have to do with a system of trinitarian doctrine."  Yet [2a] is nonetheless "the foundation of th[e] threefold division of His self-revealing action", and guarantees that "even in [2b] this differentiation of God in His revelation . . . we have to do with God Himself."

So much for the context.  But here's the point being made by Hunsinger:  "We have to" place [2b] the doctrine of God as "in His revelation" Creator, Mediator, and Redeemer, and within and behind that [2a] the doctrine of God as "in Himself and to all eternity" Father, Son, and Holy Spirit, "alongside [3] the doctrines of creation, atonement and redemption"

because [2] this Subject God Himself [and behind that the God who is [2a] "in Himself and to all eternity" Father, Son, and Holy Spirit] cannot be dissolved into His work and activity, if His work and activity is rightly to be seen and understood as His.

Here is how I put this distinction between context and use the first time round:

We must distinguish God's "work and activity" ad extra, "the actuality of the Word of God", from "the doctrine of the Trinity" considered as a "dogma," "doctrine," "basic view, or . . . controllable principle which can be used as such for the construction of a system. . . . of trinitarian doctrine."

We did not derive our differentiation of the Loci [into De creatione, De reconciliatione, De redemptione (and before those De Deo)] from the doctrine of the Trinity.  We derived the doctrine of the Trinity itself from the same source as that from which is now derived the differentiation of the Loci, viz., the work and activity of God in His revelation.

The doctrine of the Trinity, like all other doctrines, is preceded by the fact of revelation in itself and as such.  The essence of this fact is that God confronts us as Creator, Mediator, and Redeemer, that as such He speaks and deals with us, that He is therefore God and Lord in this threefold way.  This being of God in His work and activity is not a dogma, or a basic view, or a controllable principle which can be used as such for the construction of a system.  It is the actuality of the Word of God, freely preceding and underlying all views and dogmas.  We attained our differentiation of the Loci by reference to this actuality and not to the doctrine of the Trinity, although inevitably [this actuality] both confirms the latter, and is itself confirmed by it, and safeguarded against misunderstandings.

Only with what I've just placed in italics do we arrive at the use Hunsinger makes of this passage.  This use is perfectly legitimate, as indeed Barth himself makes abundantly clear

("In §§ 10-12 we thought it necessary to understand God in His revelation as Creator, Mediator and Redeemer in order to see as the foundation of this threefold division of His self-revealing action the fact that in Himself and to all eternity God is Father, Son and Holy Spirit" (and then very shortly the first of the two sentences quoted by Hunsinger)),

but not the main point here.

The dangers Hunsinger sees in the new revisionism of McCormack and company were, in my judgment, dangers for the substitution of Creator-Redeemer-Sustainer before that.