Regarding the dvar Torah by Rabbi Yair Hoffman (Nov. 1, 2018) “Every Shul Should Have an Armed Person,” I would like to quote a greater authority, i.e., Hashem told Moshe Rabbeinu that every Jew must have a gun for self-protection in Parshat Beshalach 13:18,

“V’Chamushim alu Bnei Yisrael mei’Eretz Mitzrayim, And the Jewish people went up armed from the land of Egypt.”

If that is not enough, please refer to the Rashi in Parshat Mishpatim 22:1-3: “If someone comes to kill you, act first and kill him.”

And to paraphrase the late Rabbi Meir Kahane, “Every Jew a .22, and in his house a 12-gauge shotgun too!”