Halachaהלכה

Custom and Common Usage in Halakhic Interpretation

These sources explore two related but distinct principles in Jewish law: following established communal custom (הולכין אחר מנהג העולם) and interpreting legal language according to ordinary, everyday speech (דורשין לשון הדיוט). Together they show how practical norms and popular usage shape the application of halakhah in contracts, tenancy, and commerce.

הַכֹּל כְּמִנְהַג הַמְּדִינָה

13 sources · all verified

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What the sources say

The principle of הולכין אחר מנהג העולם directs courts to follow established local practice in commercial and labor matters — as the Mishnah (Bava Metzia 103a) rules that one who receives a field must harvest or plow according to regional custom, and the Mishnah (Bava Batra 2a) extends the same rule to partners dividing a courtyard, stating explicitly "הכל כמנהג המדינה."

דורשין לשון הדיוט, by contrast, is a hermeneutical tool applied to the language of documents and vows: the Gemara (Bava Metzia 104a) records that both Rabbi Meir and Rabbi Yehuda would expound the ordinary speech of laypeople found in legal documents — meaning the informal wording of a contract generates binding halakhic consequences even without rabbinic prescription.

The two principles share a common foundation — deference to what ordinary people actually say and do — but operate in different domains: the Rambam (Mishneh Torah, Sales 26:7) applies the local-custom rule to the meaning of commercial terms in sales, while the Gemara (Nedarim 49a) applies the leshon benei adam rule to vows, concluding that apparent disputes between Tannaim dissolve once one recognizes that each sage simply reflected the ordinary usage of his own locale.

Source 1 · Chazal
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Bava Metzia 103a

בבא מציעא ק״ג א

Bava Metzia 103a

The discussion on leases and local practice shows how the law may follow the prevalent custom of a place. It is useful for comparing fixed communal norms with interpretive attention to popular usage.

מַתְנִי׳ הַמְקַבֵּל שָׂדֶה מֵחֲבֵירוֹ, מָקוֹם שֶׁנָּהֲגוּ לִקְצוֹר – יִקְצוֹר, לַעֲקוֹר – יַעֲקוֹר, לַחְרוֹשׁ אַחֲרָיו – יַחְרוֹשׁ, הַכֹּל כְּמִנְהַג הַמְּדִינָה.

Source 2 · Chazal
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Nedarim 62a

נדרים ס״ב א — ד"ה תָּנָא

Nedarim 62a:1

This sugya explicitly engages in interpreting expressions according to common, everyday usage. It is one of the classic places where חז"ל distinguish between technical language and ordinary speech.

תָּנָא: הוּקְפְּלוּ רוֹב הַמַּקְצוּעוֹת — מוּתָּרוֹת מִשּׁוּם גֵּזֶל, וּפְטוּרוֹת מִן הַמַּעַשְׂרוֹת. רַבִּי וְרַבִּי יוֹסֵי בַּר רַבִּי יְהוּדָה אִיקְּלַעוּ לְהָהוּא אַתְרָא בִּזְמַן שֶׁהוּקְפְּלוּ רוֹב הַמַּקְצוּעוֹת, רַבִּי הֲוָה קָא אָכֵיל, רַבִּי יוֹסֵי בַּר רַבִּי יְהוּדָה לָא אָכֵיל. אֲתָא מָרְהוֹן, אֲמַר לְהוּ: אַמַּאי לָא אָכְלִי רַבָּנַן? הוּקְפְּלוּ רוֹב הַמַּקְצוּעוֹת הוּא! וְאַף עַל פִּי כֵן לָא אָכֵיל רַבִּי יוֹסֵי בַּר רַבִּי יְהוּדָה, קָסָבַר: מִשּׁוּם סַנְיוּת מִילְּתָא הוּא דְּקָאָמַר הָדֵין גַּבְרָא.

The Sages taught: If most of the knives have been set aside, the figs left in the field are permitted with regard to the laws of stealing and are exempt from tithes, since their owners presumably do not want them and the figs are therefore considered ownerless property. The Gemara relates: Rabbi Yehuda HaNasi and Rabbi Yosei bar Rabbi Yehuda arrived at a certain place at a time when most of the knives had been set aside. Rabbi Yehuda HaNasi ate the figs left in the field, but Rabbi Yosei bar Rabbi Yehuda did not eat. The owner of the field came and said to them: Why are the Sages not eating? It is now the period when most of the knives have been set aside. The Gemara notes: But nevertheless, Rabbi Yosei bar Rabbi Yehuda did not eat, since he thought that it was only due to embarrassment over the matter that that man said his comment, but he did not really mean to declare his figs ownerless.

Source 3 · Chazal
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Bava Metzia 104a

בבא מציעא ק״ד א — ד"ה גְּמָ׳ רַבִּי מֵאִיר הָיָה דּוֹרֵשׁ לְשׁוֹן

Bava Metzia 104a:8

The sugya discusses whether local custom can override default legal expectations in contractual and property contexts. It is relevant to how communal norms shape interpretation and enforcement.

גְּמָ׳ רַבִּי מֵאִיר הָיָה דּוֹרֵשׁ לְשׁוֹן הֶדְיוֹט. דְּתַנְיָא, רַבִּי מֵאִיר אוֹמֵר: ״אִם אוֹבִיר וְלָא אֶעֱבֵיד אֲשַׁלֵּם בְּמֵיטְבָא״. רַבִּי יְהוּדָה הָיָה דּוֹרֵשׁ לְשׁוֹן הֶדְיוֹט. דְּתַנְיָא, רַבִּי יְהוּדָה אוֹמֵר: אָדָם מֵבִיא קׇרְבַּן עָשִׁיר עַל אִשְׁתּוֹ, וְכֵן כׇּל קׇרְבָּן וְקׇרְבָּן שֶׁהִיא חַיֶּיבֶת, שֶׁכָּךְ כּוֹתֵב לָהּ אַחְרָיוּת: דְּאִית לִיךְ עֲלַי מִן קַדְמַת דְּנָא.

GEMARA: Rabbi Meir would expound common language used in legal documents written by ordinary Jews to deduce halakhic conclusions. Although these formulations were not prescribed by the Sages, one can nevertheless infer halakhot from them if they are used in legal documents. As it is taught in a baraita that presents a similar case to the mishna: Rabbi Meir says he is liable to pay, as the document states: If I let the field lie fallow and do not cultivate it, I will pay with best-quality produce. Likewise, Rabbi Yehuda would also expound common language, as it is taught in a baraita: Rabbi Yehuda says: In a case where a woman who has given birth is commanded to bring the offering of a childbearing woman and her husband is sufficiently wealthy, a person brings the offering of the rich on behalf of his wife. This is so even if his wife does not possess money of her own and perhaps should have been considered poor. Similarly, he may bring every offering that she is obligated to bring, such as a sin offering or guilt offering. He pays for all these offerings because this is what he writes to her in her marriage contract: I accept upon myself to repay you for all obligations that you have, even those from beforehand. Consequently, he must fund all of her offerings.

Source 4 · Chazal
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Shabbat 12b

שבת י״ב ב — ד"ה וְאָמַר רַבִּי חֲנִינָא

Shabbat 12b:2

The Gemara here includes an example of interpreting ordinary speech patterns and everyday phrasing in determining meaning. It is relevant as a primary Chazal source for reading common language as people actually use it.

וְאָמַר רַבִּי חֲנִינָא: בְּקוֹשִׁי הִתִּירוּ לְנַחֵם אֲבֵלִים וּלְבַקֵּר חוֹלִים בְּשַׁבָּת. אָמַר רַבָּה בַּר בַּר חָנָה: כִּי הֲוָה אָזְלִינַן בָּתְרֵיהּ דְּרַבִּי אֶלְעָזָר לְשַׁיּוֹלֵי בִּתְפִיחָה, זִימְנִין אָמַר: ״הַמָּקוֹם יִפְקׇדְךָ לְשָׁלוֹם״. וְזִימְנִין אָמַר לֵיהּ: ״רַחֲמָנָא יִדְכְּרִינָךְ לִשְׁלָם״. הֵיכִי עָבֵיד הָכִי? וְהָאָמַר רַב יְהוּדָה: לְעוֹלָם אַל יִשְׁאַל אָדָם צְרָכָיו בִּלְשׁוֹן אֲרַמִּי. וְאָמַר רַבִּי יוֹחָנָן: כׇּל הַשּׁוֹאֵל צְרָכָיו בִּלְשׁוֹן אֲרַמִּי — אֵין מַלְאֲכֵי הַשָּׁרֵת נִזְקָקִין לוֹ, שֶׁאֵין מַלְאֲכֵי הַשָּׁרֵת מַכִּירִין בִּלְשׁוֹן אֲרַמִּי! שָׁאנֵי חוֹלֶה דִּשְׁכִינָה עִמּוֹ.

And Rabbi Ḥanina said: It was only with great difficulty that the Sages permitted to comfort the mourners and visit the sick on Shabbat, as both the visitor and the comforter experience suffering on Shabbat. They permitted it only due to the mitzva involved in these activities. Rabba bar bar Ḥana said: When we would follow Rabbi Elazar to inquire about the health of a sick person; sometimes he would say in Hebrew: May the Omnipresent remember you for peace, and sometimes he would say to him in Aramaic: May the all-Merciful remember you for peace. He would say it in Aramaic when the sick person did not understand Hebrew (Rav Elazar Moshe Horovitz). The Gemara asks: How did he do this, pray in Aramaic? Didn’t Rav Yehuda say: A person should never request that his needs be met in the Aramaic language? And, similarly, Rabbi Yoḥanan said: Anyone who requests that his needs be met in the Aramaic language, the ministering angels do not attend to him to bring his prayer before God, as the ministering angels are not familiar with the Aramaic language, but only with the sacred tongue, Hebrew, exclusively. The Gemara responds: A sick person is different. He does not need the angels to bring his prayer before God because the Divine Presence is with him.

Source 5 · Chazal
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Nedarim 49a

נדרים מ״ט א — ד"ה לֵימָא בְּהָא קָמִיפַּלְגִי

Nedarim 49a:3

The Gemara proposes that the disagreement might stem from one sage following the language of Torah while the other follows the language of people in vows, but rejects this, arguing that both follow the language of people in vows; rather, each sage stated his position according to the local terminology of his region, where the same food had different names.

לֵימָא בְּהָא קָמִיפַּלְגִי, דְּרַבִּי יֹאשִׁיָּה סָבַר: הַלֵּךְ אַחַר לְשׁוֹן תּוֹרָה, וְתַנָּא דִילַן סָבַר: בִּנְדָרִים הַלֵּךְ אַחַר לְשׁוֹן בְּנֵי אָדָם? לָא, דְּכוּלֵּי עָלְמָא בִּנְדָרִים הַלֵּךְ אַחַר לְשׁוֹן בְּנֵי אָדָם, מָר כִּי אַתְרֵיהּ וּמָר כִּי אַתְרֵיהּ. בְּאַתְרָא דְּתַנָּא דִילַן — לְצָלִי קָרוּ לֵיהּ צָלִי, וְלִמְבוּשָּׁל קָרוּ לֵיהּ מְבוּשָּׁל. בְּאַתְרָא דְּרַבִּי יֹאשִׁיָּה — אֲפִילּוּ צָלִי קָרוּ מְבוּשָּׁל.

The Gemara suggests: Let us say that they disagree with regard to this following principle, that Rabbi Yoshiya holds that one should follow the language of the Torah, and our tanna holds that with regard to vows one should follow the language of people. The Gemara refutes this suggestion: No, it is possible that everyone agrees that with regard to vows one should follow the language of people. Rather, this Sage stated his opinion in accordance with the language of his locale, and this Sage stated his opinion in accordance with the language of his locale. In the locale of our tanna, roasted food is called roasted and cooked food is called cooked, and in the locale of Rabbi Yoshiya even roasted food is called cooked.

Source 6 · Chazal
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Esther Rabbah 4

אסתר רבה ד׳ — ד"ה וַיֹּאמֶר מְמוּכָן לִפְנֵי הַמֶּלֶךְ וְהַשָֹּׂרִים

Esther Rabbah 4:6

Multiple Amoraim dispute whether Jewish legal procedure mirrors Persian procedure: some hold that it does, citing rules about which judge speaks first in different cases, while others hold it does not, and instead explain Memukhan's initiative as driven by personal motives unrelated to legal protocol.

וַיֹּאמֶר מְמוּכָן לִפְנֵי הַמֶּלֶךְ וְהַשָֹּׂרִים (אסתר א, טז), מָה רָאָה מְמוּכָן לִקְפֹּץ בְּעֵצָה תְּחִלָּה, מִכָּאן שֶׁהֶדְיוֹט קוֹפֵץ בָּרֹאשׁ. רַבִּי פִּנְחָס וְרַבִּי חִלְקִיָּה בְּשֵׁם רַבִּי סִימוֹן וְרַבִּי אֶלְעָזָר וְרַבִּי יוֹחָנָן, חַד אָמַר דִּינֵינוּ כְּדִינֵיהֶם, וָחֳרִינָא אָמַר אֵין דִּינֵנוּ כְּדִינֵיהֶם, מַאן דְּאָמַר דִּינֵינוּ כְּדִינֵיהֶם, כְּדִתְנַן דִּינֵי מָמוֹנוֹת הַטְּהָרוֹת וְהַטֻּמְאוֹת מַתְחִילִין מִן הַגָּדוֹל, וְדִינֵי נְפָשׁוֹת מַתְחִילִין מִן הַצַּד. וּמַאן דְּאָמַר אֵין דִּינֵינוּ כְּדִינֵיהֶם, מַה מְּקַיֵּם וַיֹּאמֶר מְמוּכָן, נִרְאִין דִּבְרֵי רַבִּי יְהוּדָה נִרְאִין דִּבְרֵי מְמוּכָן. רַבִּי יוֹחָנָן אָמַר תְּלָתָא אָמוֹרָאִין, חַד אָמַר עַל יְדֵי שֶׁהָיְתָה מְסַטַּרְתּוֹ בַּקּוּרְדָּקִין שֶׁלָּהּ עַל פָּנָיו לְכָאן וּלְכָאן. וָחֳרִינָא אָמַר עַל יְדֵי שֶׁלֹא הִזְמִינָה אֶת אִשְׁתּוֹ לִסְעוּדַת נָשִׁים. וָחֳרִינָא אָמַר עַל יְדֵי שֶׁהָיְתָה לוֹ בַּת, וְהָיָה מְבַקֵּשׁ לְהַשִֹּׂיאָהּ לַמַּלְכוּת. מַאן דְּאָמַר עַל יְדֵי שֶׁהָיְתָה מְסַטַּרְתּוֹ בַּקּוּרְדָּקִין שֶׁלָּהּ עַל פָּנָיו לְכָאן וּלְכָאן, שֶׁאָמַר, לֹא עַל הַמֶּלֶךְ לְבַדּוֹ עָוְתָה וַשְׁתִּי הַמַּלְכָּה. וּמַאן דְּאָמַר עַל יְדֵי שֶׁלֹא הִזְמִינָה אֶת אִשְׁתּוֹ לַסְּעוּדַת נָשִׁים, שֶׁאָמַר כִּי יֵצֵא דְּבַר הַמַּלְכָּה עַל כָּל הַנָּשִׁים לְהַבְזוֹת בַּעְלֵיהֶן בְּעֵינֵיהֶן, הָדָא הִיא דְּלָא הֲוַת תַּמָּן. מַאן דְּאָמַר עַל יְדֵי שֶׁהָיְתָה לוֹ בַּת וְהָיָה מְבַקֵּשׁ לְהַשִֹּׂיאָהּ לַמַּלְכוּת, שֶׁאָמַר וּמַלְכוּתָהּ יִתֵּן הַמֶּלֶךְ לִרְעוּתָהּ הַטּוֹבָה מִמֶּנָּה.

“Memukhan said before the king and the princes: It is not against the king alone that Vashti the queen has sinned; rather, it is against all the princes and all the peoples who are in all the provinces of Aḥashverosh the king” (Esther 1:16). What did Memukhan see that led him to leap and offer counsel first? [One can learn] from here that the ignorant leap first. Rabbi Pinḥas and Rabbi Ḥilkiya in the name of Rabbi Simon, and Rabbi Elazar, and Rabbi Yoḥanan. One said: Our legal system is like their legal system, and one said: Our legal system is not like their legal system. The one who said our legal system is like their legal system, it is as we learned (Sanhedrin 32a): In monetary laws, and in matters of ritual impurity and purity, one commences from the greatest judge. In capital laws, one commences from the side. The one who said that our legal system is not like their legal system, what is the significance of “Memukhan said?” [It is comparable to:] The statement of Rabbi Yehuda appears to be correct. [Likewise:] The statement of Memukhan appears to be correct. Rabbi Yoḥanan said there are three amora’im [who explained why Memukhan sought to depose Vashti]. One said: Because she would slap him with her slippers on this side and that. Another said: Because she did not invite his wife to the women’s banquet. And the other said: Because he had a daughter and he sought to marry her to royalty. The one who said: Because she would slap him with her slippers on this side and that, it is as he said: “It is not against the king alone that Vashti has committed an offense” (Esther 1:16). And the one who said: Because she did not invite his wife to the women’s banquet, it is as he said: “For the queen’s deed will get out to all the women, rendering their husbands contemptible in their eyes” (Esther 1:17); that [indicates that] she was not there. And the one who said: Because he had a daughter and he sought to marry her to royalty, as he said: “And may the king grant her queenship to another who is worthier than she” (Esther 1:19).

Source 7 · Chazal
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Bava Batra 2a

בבא בתרא ב׳ א — ד"ה הַשּׁוּתָּפִין שֶׁרָצוּ לַעֲשׂוֹת מְחִיצָה בְּחָצֵר –

Bava Batra 2a:1

This passage treats the force of local custom in defining boundaries and rights between neighbors. It is a foundational source for the legal status of accepted practice.

הַשּׁוּתָּפִין שֶׁרָצוּ לַעֲשׂוֹת מְחִיצָה בְּחָצֵר – בּוֹנִין אֶת הַכּוֹתֶל בְּאֶמְצַע. מָקוֹם שֶׁנָּהֲגוּ לִבְנוֹת גְּוִיל, גָּזִית, כְּפִיסִין, לְבֵינִין – בּוֹנִין; הַכֹּל כְּמִנְהַג הַמְּדִינָה. וְכֵן בַּגִּינָּה – מְקוֹם שֶׁנָּהֲגוּ לִגְדּוֹר – מְחַיְּיבִין אוֹתוֹ. אֲבָל בַּבִּקְעָה – מְקוֹם שֶׁנָּהֲגוּ שֶׁלֹּא לִגְדּוֹר – אֵין מְחַיְּיבִין אוֹתוֹ,

MISHNA: Partners who wished to make a partition [meḥitza] in a jointly owned courtyard build the wall for the partition in the middle of the courtyard. What is this wall fashioned from? In a place where it is customary to build such a wall with non-chiseled stone [gevil], or chiseled stone [gazit], or small bricks [kefisin], or large bricks [leveinim], they must build the wall with that material. Everything is in accordance with the regional custom. And similarly with regard to a garden, in a place where it is customary to build a partition in the middle of a garden jointly owned by two people, and one of them wishes to build such a partition, the court obligates his neighbor to join in building the partition. But with regard to an expanse of fields [babbika], in a place where it is customary not to build a partition between two people’s fields, and one person wishes to build a partition between his field and that of his neighbor, the court does not obligate his neighbor to build such a partition.

Source 8 · Rishonim
Verified

Beit Yosef, Choshen Mishpat 331

בית יוסף, חושן משפט של״א

Beit Yosef, Choshen Mishpat 331

The Beit Yosef gathers the Talmudic and rishonic sources on how established custom affects legal interpretation. It is a key codificatory discussion of customary practice as a legal factor.

ומ"ש בד"א שיש מנהג ידוע אבל אם אין בעיר מנהג ידוע או אפילו יש מנהג שלא להשכים ולהעריב והוא אומר אני שוכר אתכם כדין תורה חייבים לצאת מביתם בזריחת השמש וכו' שם אמר ריש לקיש פועל בכניסתו משלו ביציאתו משל ב"ה שנאמר תזרח השמש יאספון וכו' יצא אדם לפעלו וכו' וליחזי היכי נהיגי בעיר חדשה וניחזי מהיכא אתו בנקוטאי אי בעית אימא דאמר להו דאגריתו לי כפועל דאורייתא.

Source 9 · Rishonim
Verified

Tur, Choshen Mishpat 331

טור, חושן משפט של״א

Tur, Choshen Mishpat 331

The Tur brings the law of following local custom in business and tenancy matters. It is a standard halakhic bridge between the Talmud and later codifiers.

הלכות פועלים השוכר את הפועלים בסתם במקום שיש מנהג ידוע אינו יכול לשנות עליהם ממנהג המדינה לכל דבר בין לענין המזונות שצריך ליתן להם כפי המנהג: וכן לענין המלאכה יעשו כפי המנהג שאם נהגו שלא להשכים ולהעריב אינו יכול לכופם להשכים ולהעריב אפי' שמוסיף להם על שכרם כיון שלא התנה כן בשעה ששכרם:

Source 10 · Rishonim
Verified

Rashi on Bava Metzia 103a

רש"י על בבא מציעא ק״ג א — ד"ה אזדא ליה - הלך לו מזלו

Rashi on Bava Metzia 103a:14

Rashi often explains that contractual terms are understood according to the way people speak and the practice they intend. His comments help clarify how ordinary usage informs legal interpretation.

מהו דתימא מאי כזה דקאי אגודא דנהרא - שהוא חשוב ואגודא דנהרא הוא דמתני בהדיה שדרך בני אדם מקפידין בכך אבל ארכו ורחבו לא אתני בהדיה: קמ"ל - דאכולה מילתא אתני:

Source 11 · Rishonim
Verified

Mishneh Torah, Sales

משנה תורה, הלכות מכירה כ״ו:ז׳

Mishneh Torah, Sales 26:7

The passage states that the stated laws apply only where there is no established custom and no known terminology for each matter, but where custom exists regarding how a seller conducts sales or where people in that place use specific language for properties, one follows the custom and the language of that place for all transactions.

וְכֵן מָקוֹם שֶׁאֵין קוֹרִין אֶלָּא בַּיִת לְבַיִת לְבַדּוֹ אוֹ שֶׁקּוֹרִין בַּיִת לְבַיִת וְכָל סְבִיבוֹתָיו וּלְכָל שֶׁעַל גַּבָּיו הוֹלְכִין אַחַר לְשׁוֹן אַנְשֵׁי הַמָּקוֹם. וְכֵן הַדִּין בְּמוֹכֵר חָצֵר אוֹ שָׂדֶה אוֹ עִיר אוֹ מִטַּלְטְלִין בַּכּל הוֹלְכִין אַחַר הַשֵּׁמוֹת הָעֲרוּכוֹת בְּפִי הַכּל:

Similarly, in a place where the term "house" refers to the house alone, or the term "house" refers not only to the house but to all of its surroundings and everything that is upon it, we follow the meaning common in that locale. Similarly, when a person sells a courtyard, a field, a town or movable property, with regard to everything we follow the meaning of the terms that are used by all the local people.

Source 12 · Acharonim
Verified

Chokhmat Adam 69

חכמת אדם ס״ט

Chokhmat Adam 69

Chokhmat Adam discusses the legal force of common usage and communal practice in practical halakhic settings. It helps show how later authorities apply custom in lived halakhah.

כל דבר שאסור מה"ת אע"פי שמותר בהנאה אם הוא דבר המיוחד לאכילה אסור לעשות בו סחורה או להלוות עליו (ודעת כל הפוסקים דאסור מה"ת וכ"כ הפ"ח והמ"למ פ"ח מהל' מ"א) ובק"ק ווילנא נתפרץ הדבר שיש אנשים נושאים ונותני' בעופות וחיות טמאות וחביריי רבו עלי והעלימו עין מזה כי לדעת' בודאי לא ישמעו להם ומוטב שיהיו שוגגין ובאמת אי בדידי לבד הדבר תלוי הייתי מוחה בידם וע"כ ישמעו אך מה אעשה ועכ"פ בכל מקום ומקום ראוי לכל מ"ץ להשגיח ע"ז ולמחות ביד המורדים והפושעים שלא יביאו לקהלתינו ואז ממילא יתבטל גם כאן: ולקנות כדי להאכיל לפועליו יש אוסרין והמנהג פשוט לקנות לצורך פועליו:

Source 13 · Acharonim
Verified

Shulchan Arukh, Choshen Mishpat 331

שולחן ערוך, חושן משפט של״א

Shulchan Arukh, Choshen Mishpat 331

Shulchan Arukh codifies the principle that business and tenancy arrangements are often governed by local custom. This is one of the central halakhic loci for הולכין אחר מנהג העולם.

הגה לא היה מנהג בעיר או שאמר להן אני שוכר אתכם כדין תורה חייבין לצאת מביתם בזריחת השמש ולעשות מלאכה עד צאת הכוכבי' (טור ס"ד) ובערב שבת מקדים עצמו לביתו שיוכל למלאות לו חביות של מים ולצלות לו דג קטן ולהדליק את הנר (שם ס"ה בשם הירושלמי) לא היה מנהג בעיר אבל רוב אנשי העיר באין ממקו' שיש שם מנהג אזלינן בתר מנהג העיר שבאו משם הלך ממקו' שנהגו להשכים ולהעריב למקום שנהגו שלא להשכים ולהעריב או איפכא אזלינן בתר המקום ששכר שם הפועלים (נ"י ר"פ הפועלים בשם ירושלמי) ואינו קרוי מנהג אלא דבר השכיח ונעשה הרבה פעמים אבל דבר שאינו נעשה רק פעם אחת או שני פעמים אינו קרוי מנהג (ריב"ש סי' תע"ה):

If they came from a place where the custom is to work from dawn to dusk to a place where that is not the custom, or the reverse, we go according to the custom of the place in which they were hired (Nemukei Yosef on the beginning of Chapter 7 of Bava Metzia, "One Who Hires Worker", based on the Talmud Yerushalmi).