For that condemned man, the family's forgiveness was his resurrection. For us, forgiveness is new life as well.
We equate life with existence. Humans exist only in relation to other humans. Without someone to hear our voice, see our expressions, and read our words, how do we exist? How are we alive in a way that matters? "Eternal life" is a religious abstraction if we cannot find a way to live in peace on this earth.
Yet we may not want to acknowledge the existence of others. We may find others irritating or worse. This is particularly true of the person who has injured us; the one we consider our enemy. Bonhoeffer states it succinctly: "with our hearts burning with hatred, we seek to annihilate his moral and material existence". This is the hatred Jesus equated with murder. Instead Jesus modelled a new response to insult, injury, and betrayal: "Father forgive them for they don't know what they are doing." He not only modelled forgiveness, he expects forgiveness from anyone who would seek peace with God or man.
Eternal existence is only apprehended by faith. This is the same faith through which we know that peace is found through forgiveness. The parents who forgave and pardoned their son's killer understood this. Their faith led them to forgive and find peace. In the end, the families embraced. What a picture of the kingdom of God!