'With an outstretched Arm' - Should a synagogue have armed guards?

There are those who forbid one from entering [into a synagogue] with a long knife or uncovered head.

"A long knife." Since prayer lengthens one's days, and a knife shortens. And we rule that, here, it implies that with regard to a knife that is not long, there is no concern that the knife will shorten one's days...

There are utensils that are used for permitted purposes - i.e., a utensil that may be used on the Sabbath for the same purpose for which it is used during the week - e.g., a cup to drink from, a bowl to eat from, a knife to cut meat or bread, a hatchet to crack open nuts, and the like.

There are utensils that are used for forbidden purposes - i.e., a utensil that is forbidden to be used on the Sabbath for the same purpose that it is [ordinarily] used - e.g., a grinder, a mill, and the like - for it is forbidden to crush or grind on the Sabbath.

All utensils used for purposes that are permitted may be carried on the Sabbath, whether they are made of wood, earthenware, stone, or metal. [They may be moved] for the sake of the utensil, for the use of the place [it occupies], or to use it [for a purpose that is permitted].

MISHNA: Just as it is prohibited for a woman to carry out certain items unique to a woman into the public domain, the Sages said that a man may neither go out on Shabbat with a sword, nor with a bow, nor with a shield [teris], nor with an alla, nor with a spear. And if he unwittingly went out with one of these weapons to the public domain he is liable to bring a sin-offering. Rabbi Eliezer says: These weapons are ornaments for him; just as a man is permitted to go out into the public domain with other ornaments, he is permitted to go out with weapons. And the Rabbis say: They are nothing other than reprehensible and in the future they will be eliminated, as it is written: “And they shall beat their swords into plowshares and their spears into pruning hooks; nation will not raise sword against nation, neither will they learn war anymore” (Isaiah 2:4). With regard to women’s ornaments, they added that a garter placed on her leg to hold up stockings is pure and cannot become ritually impure as a utensil, and she may even go out with it on Shabbat. However, ankle chains, which were also women’s ornaments, can become ritually impure, and she may not go out with them on Shabbat. GEMARA:...We learned in the mishna that Rabbi Eliezer says: These weapons are ornaments for him. It was taught in a baraita that elaborates on this subject: The Rabbis said to Rabbi Eliezer: And since, in your opinion, they are ornaments for him, why are they to be eliminated in the messianic era? He said to them: They will not be needed anymore, as it is stated: “Nation will not raise sword against nation” (Isaiah 2:4). The Gemara asks: And let the weapons be merely for ornamental purposes, even though they will not be needed for war. Abaye said: It is just as in the case of a candle in the afternoon. Since its light is not needed, it serves no ornamental purpose. Weapons, too; when not needed for war, they serve no ornamental purpose either.

This commandment is a parable that describes two people who contend in a legal battle before the King. Although the two people were not informed in whose favor the judgment was issued, they can figure it out by looking to see who walks out still holding his weapons. Thus Israel along with the nations of the world face the Divine judgment on the Day of Atonement. We cannot tell which one emerged victorious, which is why God commanded You shall take for yourselves ... You can see from the fact that Israel emerges from before God holding its palm leaves and citrons, its lulav and etrog, that Israel emerged victorious.

"But synagogues of a city" - They would have synagogues for the public, and all were owners, and the residents of the city were not the sole owners of them.

It seems fitting to explain this that since most people are used to going there to pray, even though they don't give anything to help build it, nevertheless, since it was made with the public in mind, it's holy status is greater and then can't sell it...

And so too any obstacle that endangers life, it is a positive commandment to remove it and to be very careful around it as it is said, “Protect yourself and guard yourself." (Deuteronomy 4:9) And if he did not remove and set aside these obstacles that are dangerous, he violated the positive commandment and also violated the commandment, “Do not bring bloodguilt upon yourself” (Deuteronomy 22:8). [AJWS translation]

Evidently, Samaritans are not suspected of engaging in bestiality, yet livestock may not be sold to them, as they are suspected of selling it to gentiles. And furthermore, it is taught in a baraita: One may not sell weapons to gentiles or the auxiliary equipment of weapons, and one may not sharpen weapons for them. And one may not sell them stocks used for fastening the feet of prisoners, or iron neck chains [kolarin], or foot chains, or iron chains. This prohibition applies equally to both a gentile and a Samaritan. Abaye analyzes this baraita: What is the reason for the prohibition against selling these items to Samaritans? If we say that they are suspected of bloodshed, that is difficult: But are they suspected of this? Didn’t you say that one may seclude oneself with them, which indicates that they are not suspected of bloodshed? Rather, it is prohibited to sell these items to Samaritans because they will come to sell them to a gentile. According to this reasoning, it should likewise be prohibited to sell a donkey to a Jew who is suspected of selling animals to gentiles. And if you would say that there is a difference between a Jew and a Samaritan, as a Samaritan will likely not repent and will sell to a gentile, whereas a Jew will likely repent and not sell these items, this reasoning is incorrect. But doesn’t Rav Naḥman say explicitly that Rabba bar Avuh says: Just as the Sages said that it is prohibited to sell to a gentile, so too it is prohibited to sell to a Jew who is suspected of selling to a gentile? When Rabba heard this and realized that Abaye was correct, he ran three parasangs after the buyer who purchased his donkey to revoke the sale, as the Jew was suspected of selling to gentiles; and some say that he ran one parasang through sand. But he did not succeed in overtaking him...The Sages taught: One may not sell shields [terisin] to gentiles, despite the fact that they are used for protection, not to attack others. And some say: One may sell shields to them. The Gemara asks: What is the reason behind the opinion that prohibits selling shields to gentiles?...There are those who say: With regard to shields, this is the reason that one is not allowed to sell them to gentiles: As when their use of their weapon is finished in battle, they kill with these shields. And accordingly, the reason that some say in the baraita that one may sell shields to them is because they maintain that this is not a concern, as when their weapon is finished they flee, rather than use their shield as a weapon. Rav Naḥman says that Rabba bar Avuh says: The halakha is in accordance with the opinion cited as: Some say. Rav Adda bar Ahava says: One may not sell blocks [ashashiot] of iron to gentiles. What is the reason? It is because they forge weapons from them. The Gemara asks: If so, then even hoes and axes should not be sold to them, as they too can be used to forge weapons. Rav Zevid said in response: The ruling of Rav Adda bar Ahava was stated with regard to Indian iron, which is of a superior quality and used only for crafting weapons. The Gemara clarifies: And as for the fact that nowadays we do sell all weapons, Rav Ashi said: We sell the weapons to the Persians, who protect us.

Rabbi Moses ben Nahman (1194–1270), commonly known as Nachmanides

(20) For you were strangers in the land of Egypt: Not all strangers are made fitting [for special treatment just] because we were strangers in [some] land for a time. And there is no reason that they should be assured [of this treatment] forever because of this. And Rashi on Exodus 22:20 explained that it is the reason why "you should not oppress him with words [...], for if you oppress him, he can oppress you [also] by saying to you, 'You also come from strangers' - [regarding] a blemish in you, do not speak about it in your fellow." And Rabbi Avraham (Ibn Ezra on Exodus 22:20) said, "Remember that you were strangers like him." But I do not believe these explanations fundamentally address the issue. Rather, what is correct in my eyes is that when it states, "Do not oppress the stranger and do not harry him," you may think that he has no one to save him from your hand, since you know that you were strangers in the land of Egypt, and you saw the harrying that Egypt harried you and that I took vengeance for you, 'since I see the tear of the oppressed who has no comforter and has no power from the hand of their oppressors' and I save every person 'from the hand of one stronger than he.' And so [too], do not afflict the widow and the orphan, since I hear their cries. As all of these do not rely on themselves and [so] upon Me do they rely. And in a different verse, it adds another reason (Exodus 23:9), "For you know the feelings of the stranger, since you were strangers in the land of Egypt." This is to say, you know that any stranger has low self esteem, and he sighs and cries, and his eyes are always to God - and He will have mercy upon him, as He had mercy upon you, as it is written (Exodus 2:23), "and the Children of Israel sighed from the work and they cried out, and their prayer ascended to God, from the work." This is to say that not because of their merit [did God hear], but rather He had mercy upon them due to their [heavy] work.

Hezekiah ben Manoah (c.1250-1310)

(9) וגר לא תלחץ, “and do not oppress the stranger.” Here too the Torah speaks about the treatment strangers may have to endure at court. In the earlier reference to the stranger, (22,2), the Torah referred to how we are not to treat the stranger in every day life, not particularly when he is involved in litigation. It is repeated here as he is also one of the sections of society that is likely to be taken advantage of, as they have no one to stand up on their behalf; It is easy to get away with taking advantage of them.

Bahya ben Asher ibn Halawa (1340 – 1255)

(5) It is common courtesy to welcome newcomers with food and drink; not that the Israelites had any needs in the desert--they had Manna falling [from heaven] for them and a well that traveled with them.

Naftali Zvi Yehuda Berlin (1816-1893)

For [the Edomite] is your relative. G-d wanted to accustom Israel to the virtues of a sensitive soul. And the higher the soul, the more he brings his relatives closer. This is why he commanded him to remember the brotherhood of the Edomites.