It is a tenet of traditional Christianity that the messiah, Christ, took it upon himself to bear the weight of the world's sins. Through something that appears to be much like magic, this decision of Christ's is part of what redeems his followers, saving them from original sin and, likewise, from death. This response seems to me to be too otherworldly and too contaminated by wish fulfillment (although I could be wrong. It is very easy to be wrong about religious matters).
But what if something else is meant, entirely?
Here's an alternative explanation: Christ is representative of the individual who decides that everything that constitutes human nature, socially, also constitutes him, individually. Most human beings do not want to accept this. Who wants to believe that the capacity for criminality, torture -- and, worse, totalitarian extermination -- exists within our breasts? But it is in fact in the denial of this truth that people cut themselves off from the full expanse of human moral capacity.
What if it were impossible to understand how good a human being might be, until you were fully willing to accept that you would have been a Nazi -- even a concentration camp guard -- if you had been born in Germany at the appropriate historical moment? The development of such understanding really constitutes a full encounter with evil. Such a process is captured, mythologically, by the story of Christ encountering and overcoming Satan in the desert (which is a lonesome and desolate place).
Think about it: How could you be good, in truth, if you do not understand evil? How can you avoid participating in a process you do not understand? You might be participating right now, without even knowing it! (In fact, you probably are).
Think about this, too: If the understanding of evil is the primary impediment to enlightenment and redemption, then it is easy to understand why those virtues or properties are so rare.
It is through the encounter with radical evil, and the acceptance of personal responsibility for the existence of that evil, that man is redeemed, and spiritual death, with its attendant all-too-real hells, is avoided.
Understanding all of this also means beginning to understand the meaning of the "imitatio Christi."