And yet God, who is always merciful even when he punishes, “put a mark on Cain, lest any who came upon him should kill him” (Gen 4:15). He thus gave him a distinctive sign, not to condemn him to the hatred of others, but to protect and defend him from those wishing to kill him, even out of a desire to avenge Abel’s death. Not even a murderer loses his personal dignity, and God himself pledges to guarantee this. And it is precisely here that the paradoxical mystery of the merciful justice of God is shown forth. As Saint Ambrose writes: “Once the crime is admitted at the very inception of this sinful act of parricide, then the divine law of God’s mercy should be immediately extended. If punishment is forthwith inflicted on the accused, then men in the exercise of justice would in no way observe patience and moderation, but would straightaway condemn the defendant to punishment. … God drove Cain out of his presence and sent him into exile far away from his native land, so that he passed from a life of human kindness to one which was more akin to the rude existence of a wild beast. God, who preferred the correction rather than the death of a sinner, did not desire that a homicide be punished by the exaction of another act of homicide”.13
– St. John Paul II
