From one perspective revenge is a primitive form of law. It is unbridled, unreflective and an arbitrary act of retribution. Punishment, within the framework of law, has a purpose, is administered according to established guidelines and is dispensed on the basis of a judicial sentence. Moving from vengeance to penal law is a moral advance.
Others argue that revenge is for those outside the legal system of a group or community. The laws of the group punish transgressors within the community. Revenge is an act of self-assertion by a group against an outside attack. As such it can be an act of exclusion. The person harmed and his avenger, on one hand, and the culprit, on the other, are members of different groups. Each represents the rights and duties of the group and acts in its name.