There seems to be a lot of controversy around atonement theory, especially in regard to those who advocate for so called Penal Subsitutionary Atonement (PSA) theory, and those who don’t. I used to be a strong advocate of PSA as the touchstone of what holds all other theories of the atonement together. But I have shifted, of course. In evangelical Calvinism, along with Thomas Torrance (and others), I have advocated for the ontological theory of the atonement (I have written about that somewhere else). The underlying premise behind the ontological theory is that sin has so affected who we are as people (at an ontic level) that we need to be recreated, or in “biblical” terms, resurrected (the Apostle Paul seems to agree, see Romans 6–8). The underlying premise behind a PSA view is that God’s holy law has been broken, thus a penalty incurred, thus this penalty needs to be paid for. To further complicate this (the PSA view), all of the terms and categories it has received come through a late medieval conception of salvation known as Covenant or Federal theology; it is this basis that informs and shapes, I will assert, popular and even academic conceptions of PSA today. But without getting further into fleshing out definitions, comparisons and contrasts between PSA and the Ontological theory (among other theories), let’s hear from Christian Kettler on Karl Barth’s approach to atonement theory (it fits with the Ontological theory of the atonement that us Evangelical Calvinists believe should be primary in this ongoing discussion). Here is Kettler on Barth:
The New Testament description of this “history” [Jesus’ history] speaks of a particular, once for all event which consists of three parts. The first consists of the sayings and acts of Jesus in Galilee, where he is in control, and, in a sense, remote from others in his purity. The second part consists of Gethsemane and the Passion. Jesus is no longer the subject but the object of what happens. A judgment takes place, not upon the guilty, but upon the Judge.
The real commentary is in the third part of the story, the resurrection narrative. It tells us that the gospel story is “significant in itself.” There is no power beyond the object which can cause it to become significant. In the case of Jesus, it is the power of the Judge to take the place of those who are judged, “the power of the corresponding becoming.” Therefore our subjectivity is not something which could begin to add anything to this greatest of “facts.”
He speaks for Himself whenever He is spoken of and His story is told and heard. It is not He that needs proclamation but proclamation that needs Him. [Karl Barth]
In addition, if Christ is present today, one cannot relegate the history of Jesus Christ to the past. No, it is “a history which is the new history for every man.” The reality of salvation is found for Barth not in the history of religious experiences of humanity but in the history of one man, the man who has taken the place of humanity in judgment.
So for Karl Barth atonement theory reposes in and from God’s identification with us in the Incarnation of His Son, Jesus Christ. If we are going to have a forensic language connected to what happened in atonement, and we must, since the Bible has such language, then this is the alternative we should follow; the alternative is grounded in a thoroughgoing doctrine of the vicarious humanity of Christ. The idea that the Judge became judged for us takes the forensic components and collapses them where they need to be collapsed. Not into a quid-pro-quo Covenantal schema imposed upon Scriptural categories which gives us the Penal Substitutionary Atonement theory, but it collapses such legal language back into its rightful context as given, sustained, and realized in God’s life of Triune love for us in his elected life with us in Jesus Christ. Note Kettler further on Barth and the importance of the vicarious humanity of Christ at this point:
Barth states that Jesus Christ is “for us” because he took our place as judge. Instead of the arrogance of humanity which assumes the place of judge, God has intervened in Jesus Christ, having claimed that place for himself, and has judged the sin of humanity. This is not simply an intellectual exposure of the arrogance of humanity, but a taking away of its place by the humanity of Christ. This is the radicality of the vicarious nature of the humanity of Christ in Barth’s doctrine of the atonement. Such radicality has great implications for the comprehensiveness of the gospel, since “Jesus as very man and God has taken the place of every man.” Ethical implications are relevant here, also. This is a “replacement,” not a new prohibition or commandment from eating the fruit from the tree of knowledge of good and evil. In summary, “replacement” speaks of “vicarious humanity.”
If we are going to say that we affirm historic and orthodox Chalcedonian christology (i.e. two natures Christology), then we must follow its reduction where it leads; it leads to a radical doctrine of the vicarious humanity of Christ. He is the Judge who has freely been judged for us!
I am feeling pretty passionate about all of this as I write this, I am having to constrain myself from really saying what I think about this whole online atonement discussion that has been taking place between so called Progressive and Conservative (primarily of a certain Reformed variety) Christians. It just seems like it is missing the boat.
 Christian Kettler, The Vicarious Humanity of Christ and the Reality of Salvation (Eugene, OR: Wipf and Stock, 1991), 241.
 Ibid., 242-43.