EXOD622 If the thief is found breaking into a house at night, the Torah says that if a Jew kills that thief, he or she is blameless. This seems to give legal authority for purchasing a weapon in advance in order to kill an intruder who may break into a home. But why is this so? By what legal authority can the owner of the home become both judge and jury in one fell swoop and kill this thief, without the legal system for determining that this man is a (potential) murderer who maybe stopped with the gun? Rashi, in his commentary on this verse, gives us a clear explanation. Killing this intruder, says Rashi, is not considered murder because the Torah creates a special ruling in this case. This person, intent on murdering the occupants of the house, already has the legal status of a "dead man" (equal to a legally convicted murderer). Thus, it is lawful to kill such a person by any means necessary. But how do we know that this person is indeed a murderer, even in potential? Maybe he came only to steal some objects, but if he were to be challenged by the residents of the home, he would run away? The Talmud responds to this question by explaining that a typical thief knows that most homeowners, if the owners face him, will not simply give up their possessions. Thus, the thief who knows this in advance generally comes armed and is prepared to kill the inhabitants if confronted. Sanhedrin 72a Based on this verse and Talmudic discussion, the Talmud establishes the legality of the principle of self-defense-if someone is coming to kill you, you may kill him first. Yoma 85b In addition, God's command to the Jews to attack the Midianites who attacked the Jewish people in the desert Numbers 25:16–18 is also a basis for the concept of self defense. Midrash Tanchuma, Pinchas 3 (continued at [[EXOD626]] Exodus 22:2 sun AMJV 119)