At the core of both the "Trinity" (as revealed via the Incarnation, so that God the Son presupposes God the Father and God the Spirit is then the inevitable procession as manifested in the divine life Personally present where neither the Father nor the Son is to be understood as "localized"--consider Christ's promise to His disciples that He and the Father will come and make their abode with(in) the believer)--as I was saying, at the core of both the "Trinity," as the Church formalized this intrinsic biblical revelation, and of the Cross/Propitiation (yes, the hotly controversial teaching proclaimed universally by Christianity until, oh, about five minutes ago that Christ in His death embodied a "substitution" for us, taking the "punishment" for our sins)--let me start afresh after all that necessary preamble: at the core of both the Trinity and the Cross/Propitiation lies the essential question what it means to forgive.
And the essence of this question actually requires the deity of Christ.
Because forgiveness, if it really is forgiveness (and not a milquetoast "excusing" on the lines that "it's alright, no harm done, you didn't mean it"), means the one wronged has to swallow the brunt, the pain, of the evil done to him, and in some way die. That's the alternative to forcing...as if one could...the wrongdoer to make it all okay again. When you come right down to it no wrongdoer can ever do that, because ideally the undoing of a wrong means turning time itself back to make it so that the evil was never done. Impossible!
Thus, rather than wait, desperately, bitterly, forever, for the wrongdoer to make it right (impossible!), the one wronged makes it right within himself by killing the wrong, all its power and weight, its guilt and debt, within himself. He very nearly (or perhaps even literally) dies a death in the process. He dies to the entire life that would have been possible in the absence of that wrong. He swallows its reality and, if the digestive metaphor isn't too indelicate, expels it. Kills it within himself rather than either killing the wrongdoer or demanding the wrongdoer kill himself for it.
Thus, only the one wronged can do authentic forgiveness.
Thus, Christ must be the Wronged God swallowing all the wrong done to Him and so dying with it, killing it in his own dying, so that it is entirely expiated--the Propitiation.
On that level (infinitely beyond our penetration), one cannot fine-comb rather precious human distinctions between the "righteous judgment of God" and "the agony of the victim." They instantiate each other, are a single act. If God is the willing victim of all the wrongs done Him, then His suffering is the righteous propitiation of the selfsame wrongs. It is the suffering that itself judges sin as sin, committing at once both the judgment intrinsic to all forgiveness (since forgiveness is a verdict that evil has been done) and its remission (catharsis, putting away, propitation). The expiation is the expiation, however you cut it.
The ostensible scandal of "substitutionary theory" derives from a myopic theology that forgets for the moment, or perhaps entirely, the deity of Christ. It's a theology that might pay lip service to the Incarnation but, suddenly, when the subject is Christ and the Cross, ALL the indignant, morally superior talk is about how, no!, we could never tolerate any such primitive and inhuman (!) notion of... (major run-on sentence alert)...a God Who's so seething with rage at our human foibles that He just needs somebody to vent it all at and Jesus was the one kind enough to let a brutal Heavenly Father blast Him with unspeakably transcendent physical and, more so, spiritual agony, in order to mollify Him and, as it were, make Him look at us more kindly after getting over His divine bad mood. (Whew.)
Such is the derisive caricature of "substitution" that flows from a sullenly puerile obstinacy that, first, God MUST be reduced to the level of our political correctness and, secondly, the nature of Christ must be so compartmentalized as to exclude His deity when excluding it best serves one's theological aims.
It's all very simple to pooh-pooh the Substitution when the Christ on the cross is ONLY a man. But "Substitution" means transcendently more when the Christ on the cross is integrally and always both Man and God Incarnate. His death is the ACT of forgiveness, the materialization of God's "swallowing" the evil done Him and getting rid of it, in His Own Body ("...for the remission of sins"), rather than holding us forever hopelessly to an impossible debt.
When we ourselves forgive, REALLY forgive, it is a mini-Golgotha, because we too undergo a death, a grief, a swallowing of the thing that should never have happened but did, the loss of what we never should have lost.
We fully become one with that death so that it emerges into new life, the life after release, the life after the ultimate loss of the loss itself.
Forgiveness is death, in some way or another, but because of Christ after death comes...Resurrection. The Risen Life of Christ is the life and power in communion with which we now may enact mini-Golgothas when we too forgive. ("Forgiving one another just as God in Christ has forgiven you.") After we taste that death, for all its worth, we likewise emerge into the newness of the Third Day, the abandoned tomb, imperishable life, victory, freedom.
