Commentaire sur Bava Batra 1:5
כּוֹפִין אוֹתוֹ לִבְנוֹת בֵּית שַׁעַר וְדֶלֶת לֶחָצֵר. רַבָּן שִׁמְעוֹן בֶּן גַּמְלִיאֵל אוֹמֵר, לֹא כָל הַחֲצֵרוֹת רְאוּיוֹת לְבֵית שָׁעַר. כּוֹפִין אוֹתוֹ לִבְנוֹת לָעִיר חוֹמָה וּדְלָתַיִם וּבְרִיחַ. רַבָּן שִׁמְעוֹן בֶּן גַּמְלִיאֵל אוֹמֵר, לֹא כָל הָעֲיָרוֹת רְאוּיוֹת לְחוֹמָה. כַּמָּה יְהֵא בָעִיר וִיהֵא כְאַנְשֵׁי הָעִיר, שְׁנֵים עָשָׂר חֹדֶשׁ. קָנָה בָהּ בֵּית דִּירָה, הֲרֵי הוּא כְאַנְשֵׁי הָעִיר מִיָּד:
Il [un occupant d'une cour qui ne souhaite pas aider les autres] est obligé de construire un portillon pour la cour, [où le gardien de la porte peut s'asseoir à l'ombre et empêcher les passants du domaine public de regarder dans le cour], et (il est obligé de construire) une porte [pour la porte de la cour]. R. Shimon n. Gamliel dit: Toutes les cours ne nécessitent pas de portillon. [Une cour non attenante au domaine public ne nécessite pas de portillon. La halakha n'est pas conforme à R. Shimon b. Gamliel. Car même si elle ne touche pas au domaine public, il y a parfois une presse de gens et ils convergent vers la cour.] R. Shimon b. Gamliel dit: Toutes les villes n'ont pas besoin d'un mur. [Une ville non proche de la frontière de l'ennemi n'a pas besoin de mur. La halakha n'est pas conforme à R. Shimon b. Gamliel. Même s'il n'est pas proche de la frontière de l'ennemi, il faut un mur, car des bandes armées y viennent parfois.] Combien de temps quelqu'un doit-il rester dans une ville pour être considéré comme l'un de ses habitants [pour partager les responsabilités communautaires]? Douze mois. [Mais de nos jours, qu'il y a plus de mouvement, le délai habituel est de trente jours.] Si l'on achète un logement, il est immédiatement considéré comme un habitant de la ville.
Bartenura on Mishnah Bava Batra
English Explanation of Mishnah Bava Batra
They compel [a resident of the town to contribute to] the building of a wall for the town and double doors and a bolt. Rabban Shimon ben Gamaliel says: “Not every town is fit for a wall.”
How long must a man dwell in a town to count as one of the men of the town? Twelve months. If he has purchased a dwelling place he immediately counts as one of the men of the town.
Mishnah five deals with the obligation of a person who shares a courtyard with another to help in building certain parts of the courtyard. The second half of the mishnah deals with the obligations that residents of a town have to participate in the costs of building the public structures in the town.
Section one teaches that a person who holds joint possession of a courtyard can be compelled to share in the costs of building a gate-house (where a guard would sit and protect the homes attached to the courtyard) and a door. Since these are necessities of a courtyard, one must participate in their cost. Rabban Shimon ben Gamaliel points out that not all courtyards need a gate-house. Assumedly smaller courtyards can be protected without building a gate-house. Therefore, a person would be obligated to help pay for building a gate-house only as long as the courtyard was fit for one.
Section two discusses similar laws with regards to people who live in a town. Just as in modern society people pay taxes in order to pay for the building and upkeep of town property, so too in the times of the Mishnah people had to jointly pay for the building of a wall, double-doors and a bolt to help protect the town. Again Rabban Shimon ben Gamaliel points out that not all towns are fit for walls. If the town was not a one which would usually have a wall, the residents are not obligated to share in its costs.
Finally, section three discusses how long a person must dwell in the town in order to be an official resident and thereby be obligated to pay for building its wall. There are two criteria. First of all, if he dwells in the town for twelve months he is obligated to pay. Second, if he purchases property in the town, he is immediately obligated, even if he doesn’t dwell there.