The following is from A Short Primer for Unsettled Laymen (Ignatius Press, 1985).
Without a doubt, at the center of the New Testament there stands the Cross, which receives its interpretation from the Resurrection.
The Passion narratives are the first pieces of the Gospels that were composed as a unity. In his preaching at Corinth, Paul initially wants to know nothing but the Cross, which “destroys the wisdom of the wise and wrecks the understanding of those who understand”, which “is a scandal to the Jews and foolishness to the gentiles”. But “the foolishness of God is wiser than men, and the weakness of God is stronger than men” (1 Cor 1:19, 23, 25).
Whoever removes the Cross and its interpretation by the New Testament from the center, in order to replace it, for example, with the social commitment of Jesus to the oppressed as a new center, no longer stands in continuity with the apostolic faith. He does not see that God’s commitment to the world is most absolute precisely at this point across a chasm.
It is certainly not surprising that the disciples were able to understand the meaning of the Cross only slowly, even after the Resurrection. The Lord himself gives a first catechetical instruction to the disciples at Emmaus by showing that this incomprehensible event is the fulfillment of what had been foretold and that the open question marks of the Old Testament find their solution only here (Lk 24:27).
Which riddles? Those of the Covenant between God and men in which the latter must necessarily fail again and again: who can be a match for God as a partner? Those of the many cultic sacrifices that in the end are still external to man while he himself cannot offer himself as a sacrifice. Those of the inscrutable meaning of suffering which can fall even, and especially, on the innocent, so that every proof that God rewards the good becomes void. Only at the outer periphery, as something that so far is completely sealed, appear the outlines of a figure in which the riddles might be solved.
This figure would be at once the completely kept and fulfilled Covenant, even far beyond Israel (Is 49:5-6), and the personified sacrifice in which at the same time the riddle of suffering, of being despised and rejected, becomes a light; for it happens as the vicarious suffering of the just for “the many” (Is 52:13–53:12). Nobody had understood the prophecy then, but in the light of the Cross and Resurrection of Jesus it became the most important key to the meaning of the apparently meaningless.
Did not Jesus himself use this key at the Last Supper in anticipation? “For you”, “for the many”, his Body is given up and his Blood is poured out. He himself, without a doubt, foreknew that his will to help these” people toward God who are so distant from God would at some point be taken terribly seriously, that he would suffer in their place through this distance from God, indeed this utmost darkness of God, in order to take it from them and to give them an inner share in his closeness to God. “I have a baptism to be baptized with, and how I am constrained until it is accomplished!” (Lk 12:50).
It stands as a dark cloud at the horizon of his active life; everything he does then-healing the sick, proclaiming the kingdom of God, driving out evil spirits by his good Spirit, forgiving sins-all of these partial engagements happen in the approach toward the one unconditional engagement.
As soon as the formula “for the many”, “for you”, “for us”, is found, it resounds through all the writings of the New Testament; it is even present before anything is written down (cf. i Cor 15:3). Paul, Peter, John: everywhere the same light comes from the two little words.
What has happened? Light has for the first time penetrated into the closed dungeons of human and cosmic suffering and dying. Pain and death receive meaning.
Not only that, they can receive more meaning and bear more fruit than the greatest and most successful activity, a meaning not only for the one who suffers but precisely also for others, for the world as a whole. No religion had even approached this thought.  The great religions had mostly been ingenious methods of escaping suffering or of making it ineffective. The highest that was reached was voluntary death for the sake of justice: Socrates and his spiritualized heroism. The detached farewell discourses of the wise man in prison could be compared from afar to the wondrous farewell discourses of Christ.
But Socrates dies noble and transfigured; Christ must go out into the hellish darkness of godforsakenness, where he calls for the lost Father “with prayers and supplications, with loud cries and tears” (Heb 5:7). Why are such stories handed down? Why has the image of the hero, the martyr, thus been destroyed? It was “for us”, “in our place”.
One can ask endlessly how it is possible to take someone’s place in this way. The only thing that helps us who are perplexed is the certainty of the original Church that this man belongs to God, that “he truly was God’s Son”, as the centurion acknowledges under the Cross, so that finally one has to render him homage in adoration as “my Lord and my God” Jn 20:28).
Every theology that begins to blink and stutter at this point and does not want to come out with the words of the Apostle Thomas or tinkers with them will not hold to the “for us”. There is no intermediary between a man who is God and an ordinary mortal, and nobody will seriously hold the opinion that a man like us, be he ever so courageous and generous in giving himself, would be able to take upon himself the sin of another, let alone the sin of all. He can suffer death in the place of someone who is condemned to death. This would be generous, and it would spare the other person death at least for a time.
But what Christ did on the Cross was in no way intended to spare us death but rather to revalue death completely. In place of the “going down into the pit” of the Old Testament, it became “being in paradise tomorrow”. Instead of fearing death as the final evil and begging God for a few more years of life, as the weeping king Hezekiah does, Paul would like most of all to die immediately in order “to be with the Lord” (Phil 1:23). Together with death, life is also revalued: “If we live, we live to the Lord; if we die, we die to the Lord” (Rom 14:8).
But the issue is not only life and death but our existence before God and our being judged by him. All of us were sinners before him and worthy of condemnation. But God “made the One who knew no sin to be sin, so that we might be justified through him in God’s eyes” (2 Cor 5:21).
Only God in his absolute freedom can take hold of our finite freedom from within in such a way as to give it a direction toward him, an exit to him, when it was closed in on itself. This happened in virtue of the “wonderful exchange” between Christ and us: he experiences instead of us what distance from God is, so that we may become beloved and loving children of God instead of being his “enemies” (Rom 5:10).
Certainly God has the initiative in this reconciliation: he is the one who reconciles the world to himself in Christ. But one must not play this down (as famous theologians do) by saying that God is always the reconciled God anyway and merely manifests this state in a final way through the death of Christ. It is not clear how this could be the fitting and humanly intelligible form of such a manifestation.
No, the “wonderful exchange” on the Cross is the way by which God brings about reconciliation. It can only be a mutual reconciliation because God has long since been in a covenant with us. The mere forgiveness of God would not affect us in our alienation from God. Man must be represented in the making of the new treaty of peace, the “new and eternal covenant”. He is represented because we have been taken over by the man Jesus Christ. When he “signs” this treaty in advance in the name of all of us, it suffices if we add our name under his now or, at the latest, when we die.
Of course, it would be meaningless to speak of the Cross without considering the other side, the Resurrection of the Crucified. “If Christ has not risen, then our preaching is nothing and also your faith is nothing; you are still in your sins and also those who have fallen asleep . . . are lost. If we are merely people who have put their whole hope in Christ in this life, then we are the most pitiful of all men” (1 Cor 15:14, 17-19).
If one does away with the fact of the Resurrection, one also does away with the Cross, for both stand and fall together, and one would then have to find a new center for the whole message of the gospel. What would come to occupy this center is at best a mild father-god who is not affected by the terrible injustice in the world, or man in his morality and hope who must take care of his own redemption: “atheism in Christianity”.
 For what is meant here is something qualitatively completely different from the voluntary or involuntary scapegoats who offered themselves or were offered (e.g., in Hellas or Rome) for the city or for the fatherland to avert some catastrophe that threatened everyone.