251 Those who truly forgive do not forget. Instead, they choose not to yield to the same destructive force that caused them so much suffering. They break the vicious circle; they halt the advance of the forces of destruction. They choose not to spread in society the spirit of revenge that will sooner or later return to take its toll. Revenge never truly satisfies victims. Some crimes are so horrendous and cruel that the punishment of those who perpetrated them does not serve to repair the harm done. Even killing the criminal would not be enough, nor could any form of torture prove commensurate with the sufferings inflicted on the victim. Revenge resolves nothing.
Source: Fratelli Tutti (Vatican.va)