First of all, I would like to extend my personal condolences, together with those of my colleagues and the entire Gateways Organization, to the families of the victims of these horrific acts of murder. There are no words to express the pain and suffering shared by anyone with even an iota of humanity and moral fiber. And may all who are injured have a speedy and complete recovery with the help of God.
Regarding self-defense, it is a mitzvah for a person to protect the life given to him from Above. This includes not only taking measures to avoid danger, but also taking active measures to remove danger if/when faced with it. For the same reason it is a mitzvah to save the life of a fellow human being.
Our Sages teach, “If someone comes to kill you, rise up and kill him first.” (San. 72a) The right to self-defense is well established within Jewish law as manifested by the law of rodef (a pursuer). In addition, a verse states, “You shall not stand idly by the blood of your neighbor” (Lev. 19:16). This not only demands saving a friend from drowning or other dangerous situations but further dictates that one stop an assailant from committing murder.
By the way, one should not be misled by the verse in the Ten Commandments that says “Lo Tirtzach”. Some people misunderstand this and translate it as “Do not kill”. However, the correct translation is “Do not murder”. Killing in certain circumstances is in fact permitted and even a mitzvah of the Torah as explained above.
The Torah doesn’t specifically mention guns because they did not exist in the time of the Torah or the Talmud. However, we are taught by Jewish Law to observe the laws of the land in which we reside. Therefore, if owning a gun is permitted, and a person feels — after weighing the pros and cons — that it would increase his or his family’s safety, it would be permitted to purchase and possess a gun according to the local laws.
All this applies to use of a gun for self-defense. Using a gun for hunting (i.e., for sport), however, is a subject of discussion as to whether or not it is prohibited according to Jewish Law (and if so, if it’s a Torah or Rabbinical prohibition). The opinion of the great Torah scholar and legal authority Rabbi Landau, the “Noda B'Yehuda”, is that it is definitely “not a Jewish trait or characteristic to hunt animals, and should not be done”.
Aside from the human attempts to protect life and provide for self-defense, I feel that it is important to add another aspect to this discussion: Prayers and good deeds that serve as merits for protection from Above.
