Some of the best fiction ever written in SF or anywhere else has been about redemption. The Stars My Destination-- which is on my short list for the greatest SF novel ever written-- is about a man who pursues revenge only to have it backfire on him and make him re-examine what he's doing.
Redemption is not possible without the concept of forgiveness and modern western society has Christianity to thank for that.
Now, I am not a Christian. I am an atheist. Religion is essentially an emotional decision and theism never appealed to me. But that's not to say there's not good stuff there.
So I'm going to tackle it.
Let me set the stage.
Rome conquers Jerusalem in 63 BCE and promptly installed Herod the Great as king. HTG had a fairly good relationship with Rome. He brought in a lot of Roman ideas-- put Roman idols in inappropriate
places, used Roman architecture and slaughtered a whole lot of those
that opposed him. Since Israel considered itself a religious state, tribute to Rome and taxes to Herod for what seemed to be idolatrous purposes served as seeds for later uprisings. Herod died in 4 BCE and the Romans appointed his sons and military governors to succeed him.
It's 6 CE and Judea transformed into a Roman Imperial Province. Judas of Galilee leads a revolt-- he is considered by some the founder of the Zealots: theocratic nationalists. God is the ruler of Israel and no taxes should be sent to Rome. It was not successful. JOG's death is not recorded but we can presume it was unpleasant. Two of his sons were later crucified. Later another "son"-- or relative- became a leader of the Sicarii.
Israel doesn't occupy easily. Think modern Iraq and Afghanistan. They don't take well to occupation either.
We can imagine Roman (or Herodian) retaliation. Crucifixion was introduced to the area by the Romans.
The general accepted birth year of Jesus is between 6 and 4 BCE. So, at the time Judea was transformed into a province, Jesus would have been between 10 and 12 years old. Old enough to start a trade. Old enough to be betrothed. Certainly, old enough to understand what is going on around him.
And what does he see? Devout Zealots carrying out assassinations only to find whole families slaughtered by Roman retaliation. The temple compromised by HTG. I suspect he watched a chain of people attacking Romans, getting destroyed. Bent on revenge, their children attacked later and then were killed. On and on and on in a spinning wheel of retaliation. And for what? A bit of land? A failed messiah? An attempt at exchanging a foreign appointed king for one appointed by the temple?
The message of Jesus, to turn the other cheek, to break the cycle of revenge, doesn't surprise me given that environment. What surprises me is that he didn't start preaching for another twenty years. What triggered the change from obscure worker to reformer? Was it a gradual process or sudden?
But the environment he lived in dictated that he was not talking about little things. "Turning the other cheek" was pure metaphor. He was talking about forgiving Romans for crucifying your brother or your daughter. Forgiving the Emperor for sticking such horrible people into power. He wanted to take care of the poor-- which were everywhere-- and discharging debt. He was, in point of fact, asking his followers to do pretty much everything that modern society enjoins us not to do. Matthew 19:24: "...it is easier for a camel to pass through the eye of a needle than for a rich man to enter the kingdom of God."
He was saying that what we consider the normal path: revenge, seeking prosperity, hatred-- all those things need to be released. He's talking about forgiving big debts, not small ones. Forgiving Hitler for the Holocaust. Pol Pot for the Killing Fields. The Southern Aristocracy for owning slaves in the antebellum south and for trying to oppress former slaves later.
This, by the way, is why I always liked Martin Luther King, Jr. Not for standing up for justice. But for standing up for justice in such a way as to break a cycle of revenge. For pursuing change without revenge.
Jesus did not try to reform the sinner-- he that did the strike. He went after the sinee: he that was struck. He knew that the relationship had to be changed fundamentally and that changed had to start not from the aggressor but from the victim. The victim had to be the one to forgive.
Most narratives start with the aggressor-- he who must redeem himself. But the core of redemption is to realize that wrong has been done and must be righted. That means the relationship the aggressor must realize the relationship with the victim has changed-- which means the nature of the victim must change in the eyes of the aggressor. That can't happen if the victim responds to aggression with aggression-- such behavior justifies the aggressor in the first place. I swing a punch at someone and they respond with a punch, my first punch is justified since now that person is someone to hit.
In The Stars My Destination, Gully Foyle is abandoned to die in space and spends the rest of the book looking to torture the ones responsible. Along the way he meets and falls in love with a crippled woman who hates the world. He discovers finally that she is the person responsible for his abandonment along with other atrocities. She has acted out of revenge on the world that formed her and pitied her. He is acting out of revenge against the people that abandoned him. He gives up his revenge and asks for punishment. (There's lots of other things going on in the novel.) His redemption is only possible by giving up on his revenge and, in fact, asking the world to take it out on him.
One of the truly weird things in the modern world is watching people professing to be devout Christians-- and I have no reason to doubt them-- using words like "unforgivable." Or clearly wanting revenge for a wrong in the name of "justice." Justice is not revenge. I'm not even sure it should be punishment. If someone kills my son and I want them to die in return, is that justice? I don't think so, regardless of how much I might want it to happen. It is revenge.
Would I be satisfied if the murderer was rehabilitated to the point he understood the magnitude of my suffering? To then become redeemed? Probably not-- I'm a primitive creature at heart. I suspect my anger and hatred would overcome my shriveled better nature.