The Good News is not that God made some external determination to forgive man, superficially exercised his divine will, waved a disinterested wand and sprinkled some salvation dust across the human race. What he did was penetrate the very depths of humanity’s being and life, to restore the distorted and corrupt condition of man’s actual human existence. In his innermost being as the Son he genuinely united himself to human, finite, creaturely existence. We call that the incarnation.
God himself bore our infirmities and sins and the whole inheritance of judgment that lay against us—God himself, not merely in some extrinsic, detached way. He personally bore all of this.
Incidentally, it is important to not evade this point by denying that Jesus assumed our fallen, mortal human nature. The Greek culture where the Gospel was preached held to the apathy or passionlessness of the divine nature. In order to avoid the revolutionary doctrine of God presented in the Scriptures, the heresy of aphthartodocetism was invented. The error here is to say that Jesus took to himself a flawless human nature, one that was not affected by the curse. God himself didn't really suffer, he only appeared to do so. Jesus' mind and body were not subject to sickness, weakness, and the liabilities of our mortal existence. That, of course, frees God from any contact with the yuckiness of mortal human existence as we experience it.
But this is not what we read in the Scriptures. Jesus, as true God, was also a man like us subject to our frailties though without sin. This is not only essential to his being our Savior; it is precisely the way the Son has revealed the true character of God to us. If the weakness, suffering, and death of Jesus was simply that of a good man from Nazareth, then God is inevitably bound to become a cold, silent, unknown heavenly power. And even if God had united himself with a pre-fall Adamic human nature, somehow remaining aloof and detached from the weakness as suffering associated with humanity's present condition, then that would be the end of the Christian faith. What Jesus’ birth—and then, of course, his life as a mortal man—manifests to us is the willing suffering of the passionate God.