NUM407 There are two specific scenarios in which the emotion of revenge is most natural, and the Torah allows the emotion to be acted upon, but only in a supervised manner. The first case involves witnesses to a heinous crime who see a murderer killing an innocent person in cold blood. It is very natural for anyone seeing such an act to try to avenge the innocent victim and take revenge upon that murderer. Jewish law does not allow the witness to "take the law into his own hands" and kill that murderer on the spot as an act of revenge, no matter how justified. Rather, the witness must alert the authorities and bring this evil person to a court proceeding and then testify there (Maimonides, Hilchot Rotze'ach 1:5). But the feelings of that witness are still inside. It is for this reason that when the murderer is found guilty, the Torah commands that the witnesses actually take their active revenge by being the first to kill the murderer in the court supervised execution (Deuteronomy 17:7) In describing this execution, Maimonides emphasizes how it is the witnesses who must take the lead in the execution (Maimonides, Hilchot Rotze'ach 15:1). There are often others involved in every murder case who feel an even greater desire to take revenge against the murderer--the relatives of the victim. The Torah acknowledges these intense feelings of revenge and says that under certain circumstances, the relative of a murdered person can indeed take revenge and killed a murderer [this verse]. When there is a case of deliberate and intentional murder, Maimonides rules that the relatives, those who stand to inherit, are like the witnesses and therefore at the forefront of the execution (Maimonides, Hilchot Rotze'ach 1:2) Thus, their sense of attribution can be satisfied by taking part in the killing of the person who murdered the relative.