The word 'redemption' comes from the verb 'to redeem', as in to buy back, to repurchase at a price. In the context of the Old Testament, redemption is the deliverance of Israel from Egyptian slavery. Christ is redeemer, and this means that just as through Moses, God delivered the covenant people of Israel from Egyptian slavery, Jesus delivered humanity from the slavery of sin and its consequences, namely death. What was the means of exchange through which he bought us back? His own blood, that is, his life.
But what exactly does this mean? How does this work exactly? As a teacher, I was inclined to employ a "quantitative" or juridical model to explain this to adolescents, one that has its roots in St. Anselm. The reason is that the adolescent mind finds this easy to grasp, and making sense out of mystery is attractive to them. The basic idea is that sin creates an infinite debt, that is, a debt of infinite weight, and man, who is finite, cannot make up for a sin that is of infinite gravity or weight. Only God can do so. But God is not in debt-we are, and so it is up to man to make reparation for his sin, not God. But man cannot do so, because everything he offers is of finite value. Since man cannot make reparation, he simply cannot save himself. In short, our situation is hopeless.
God, however, provides a solution. The second Person of the Trinity joins a human nature; Jesus is fully God and fully man, two natures, one Person. As man, he can go before the Father and offer a sacrifice of reparation on our behalf; as God the Son, his offering has infinite value and can cancel our debt.
This is an attractive way of explaining Christ's redemption, because it "makes sense" out of what is otherwise profoundly mysterious. Although some of what is said within this model has some truth, it is, however, a deficient model. It is far too juridical, and mystery really cannot be explicated using such narrow terms without serious consequences.
It is indeed the case that man is a slave to sin. Just as we inherit talents and dispositions from our parents or distant relatives, not to mention trauma undergone by relatives three or so generations back, we also inherit negative proclivities and sinful dispositions. This is what is meant by the wound of Original Sin called concupiscence-an inclination to sin and self-seeking. What this underscores among other things is man's profoundly social nature. Original Sin is an inherited addiction, a proclivity. The first parents of the human race made a radical decision to be their own god, sufficient unto themselves (symbolized in the image of the tree of the knowledge of good and evil that stands independent and tall). We are the offspring of the first parents, and we are born into a concrete and universal situation they created. We are affected by their sin. We are born into a situation characterized by the loss of interior grace; for man was originally created in a state of grace, in the state of original justice (with the gift of bodily immortality, freedom from concupiscence, and a sense of the divine rooted in grace). We are not born "deified" by grace, and so we are deprived of the light of grace. We cannot free ourselves from that proclivity to sin and self-seeking, for it is a genuine slavery, and no slave can free himself or herself-otherwise it is not slavery.
But God the Son drew close to us. He joined a human nature to himself and dwelt among us. The light entered into the darkness:
For God did not send his Son into the world to condemn the world, but that the world might be saved through him. Whoever believes in him will not be condemned, but whoever does not believe has already been condemned, because he has not believed in the name of the only Son of God. And this is the verdict, that the light came into the world, but people preferred darkness to light, because their works were evil. For everyone who does wicked things hates the light and does not come toward the light, so that his works might not be exposed. But whoever lives the truth comes to the light, so that his works may be clearly seen as done in God (Jn 3, 17-21).
We crucified the Son of God. Christ is Light from Light, true God from true God, and so the light entered into the darkness of our death, injecting it with his light and life. He destroyed our death, making it a means to eternal life. In joining himself to a human nature, God the son joined himself to every man/woman, as it were. The Word (logos) is present at the deepest level of our being. This does not mean that we all exist in a state of sanctifying grace. Rather, he is there, and he offers us sufficient grace to move towards him, to allow him into our lives, to reign over our own mind and heart. His death was an offering to God the Father on our behalf, an act of religion, and his offering is an acceptable one, since it is a perfect offering, rooted in a perfect divine love for the Father and for us, who come from God.
Some years ago my daughter, my wife and I went to Italy with a friend of ours, who is Italian. And he took us north, and south, and in the middle, and my daughter loved it, and she was focused primarily on shopping. I hated going into shops to look for purses or dresses, I just wanted to explore the narrow streets and old churches. It was hot, always watching out for pickpockets, not enough time to visit the places I wanted to visit, so for me it was a very unpleasant trip. The following year, however, I had the opportunity to go again, this time without my wife and daughter, just a priest friend of mine and a good friend who is also a teacher. His parents own an apartment in Rome, so we spent two weeks there. What I found fascinating upon reflection was that I spent so much time visiting the fashion district, Via Del Corso, clothing shops, looking for purses, etc. I was doing a lot of shopping for my daughter, to bring things back for her, and I was enjoying it. I wanted to visit the places that she loved. I started to love these places, because there was something of her that was left behind. I couldn't care less about the Trevi Fountain or the Spanish Steps, but because she loved those places, I had a very real desire to visit them again, but only because I was looking to recapture her presence. These places were dear to her, so they became dear to me.
I think this is a useful illustration of a profound theological truth. As was said above, God the Son joined a human nature to himself (Christ is two natures, but one Person). God the Son enters into human suffering because he loves the Father, desires his glory above all, and since we belong to God, he loves us and will not allow us to suffer alone. And that is why when God the Father sees humanity, he sees his Son. He delights in the individual human person because Christ does. The Father loves us because the Son loves us. "The kingdom of heaven is among you" means that the redemptive presence of the Second Person of the Trinity permeates this world, through the power of the reconciling Spirit.
We are redeemed by the Incarnation of the Son of God, by his entire life, which of course includes his death. God sees each one of us when he beholds his Son, and so the Son's entire life and his offering of himself in the end redeems us, buys us back from darkness to light, from alienation from God to proximity to God in him, in Christ. And all of this was pure gift, pure grace. And so a better model for understanding something of our redemption is the story of Jesus' encounter with Zacchaeus.
He came to Jericho and intended to pass through the town. Now a man there named Zacchaeus, who was a chief tax collector and also a wealthy man, was seeking to see who Jesus was; but he could not see him because of the crowd, for he was short in stature. So he ran ahead and climbed a sycamore tree in order to see Jesus, who was about to pass that way. When he reached the place, Jesus looked up and said to him, "Zacchaeus, come down quickly, for today I must stay at your house." And he came down quickly and received him with joy. When they all saw this, they began to grumble, saying, "He has gone to stay at the house of a sinner." But Zacchaeus stood there and said to the Lord, "Behold, half of my possessions, Lord, I shall give to the poor, and if I have extorted anything from anyone I shall repay it four times over." And Jesus said to him, "Today salvation has come to this house because this man too is a descendant of Abraham. For the Son of Man has come to seek and to save what was lost" (Lk 19, 1-10).
Perhaps we can look at Zacchaeus as an image of humanity. He climbs the sycamore tree, as Adam (humanity) aspires to be more than what he is by eating from the tree of the knowledge of good and evil. Jesus approaches Zacchaeus, not the other way around, and tells him to descend, for the Son of God descended and took the form of a slave, becoming obedient to death, death on a cross (Phil 2, 1-11). In Christ, we descend from the tree of the knowledge of good and evil and embrace our status as "children", dependent upon God. Christ was not invited into Zacchaeus' home; rather, he invited himself. And the result was a complete change of heart in Zacchaeus (metanoia). He was redeemed, bought back from the slavery of sin, all as a result of the approach of Christ.
Without the Incarnation, the suffering, death and resurrection of the Son of God, we would still be in our sins, still in darkness, still slaves of sin. We simply cannot save ourselves. Christ is savior. He came to save. And the gospel is a message of salvation. That is redemption.