אורח חיים שפ״זOrach Chayim 387

Se’if 1א׳

הַמִּשְׁתַּתְּפִין בְּמָבוֹי צְרִיכִים לְעָרֵב בַּחֲצֵרוֹת כְּדֵי שֶׁלֹּא יִשְׁכְּחוּ הַתִּינוֹקוֹת תּוֹרַת עֵרוּב, שֶׁהֲרֵי אֵין הַתִּינוֹקוֹת מַכִּירִים מַה נַּעֲשֶׂה בַּמָּבוֹי. לְפִיכָךְ אִם נִשְׁתַּתְּפוּ בְּמָבוֹי בְּפַת, סוֹמְכִין עָלָיו וְאֵין צְרִיכִין לְעָרֵב בַּחֲצֵרוֹת שֶׁהֲרֵי הַתִּינוֹקוֹת מַכִּירִים בְּפַת. וְיֵשׁ אוֹמְרִים שֶׁאִם לֹא עֵרְבָה כָּל חָצֵר לְעַצְמָהּ, אֵין סוֹמְכִין עַל הַשִּׁתּוּף; אֲבָל כְּשֶׁכָּל חָצֵר עֵרְבָה לְעַצְמָהּ, וְאַחַר כָּךְ נִשְׁתַּתְּפוּ בַּמָּבוֹי וְלֹא עֵרְבוּ דֶּרֶךְ פְּתָחִים שֶׁבֵּינֵיהֶם, מֻתָּרִים לְהִשְׁתַּמֵּשׁ בַּחֲצֵרוֹת שֶׁבַּמָּבוֹי דֶּרֶךְ פְּתָחִים שֶׁבֵּינֵיהֶם, שֶׁסוֹמְכִים עַל שִׁתּוּף בִּמְקוֹם עֵרוּב. וְאִם עֵרְבוּ דֶּרֶךְ פְּתָחִים שֶׁבֵּינֵיהֶם וְלֹא נִשְׁתַּתְּפוּ בַּמָּבוֹי, מֻתָּרוֹת לְהִשְׁתַּמֵּשׁ הַחֲצֵרוֹת בַּמָּבוֹי, שֶׁסוֹמְכִים עַל עֵרוּב שֶׁעֵרְבוּ הַחֲצֵרוֹת דֶּרֶךְ פְּתָחִים בִּמְקוֹם שִׁתּוּף. הַגָּה: וְיֵשׁ אוֹמְרִים דְּסוֹמְכִין אַשִּׁתּוּף בִּמְקוֹם עֵרוּב אֲפִלּוּ לֹא נִשְׁתַּתְּפוּ אֶלָּא בְּיַיִן, וְכֵן סוֹמְכִין אָעֵרוּב בִּמְקוֹם שִׁתּוּף (הָרֹא"שׁ וְהַמָּרְדְּכַי פ' הַדָּר וְטוּר). וּלְעֵיל, סי' שס"ו (ס"ז בהג"ה), כָּתַבְתִּי דְּאָנוּ נוֹהֲגִין לְכַתְּחִלָּה שֶׁלֹּא לַעֲשׂוֹת רַק שִׁתּוּף אֶחָד בְּקֶמַח; וְנִרְאֶה לִי הַטַּעַם כִּי עֵרוּב שֶׁלָּנוּ שֶׁכָּל אֶחָד מִבְּנֵי הֶחָצֵר נוֹתֵן לַשִּׁתּוּף, הָוֵי כְּעֵרוּב וְשִׁתּוּף בְּיַחַד, וּלְכַתְּחִלָּה אֵין לַעֲשׂוֹת יוֹתֵר. וְהָא שֶׁהִצְרִיכוּ שִׁתּוּף וְעֵרוּב, הַיְנוּ בִּזְמַן הַגְּמָרָא שֶׁבְּנֵי הֶחָצֵר לֹא נָתְנוּ לְשִׁתּוּף, רַק הֶחָצֵר עֵרְבוּ בְּיַחַד וְאֶחָד מִבְּנֵי הֶחָצֵר נוֹתֵן לַשִּׁתּוּף, אֲבָל בִּכְהַאי גַּוְנָא כֻּלֵּי עָלְמָא אֵין עוֹשִׂין רַק שִׁתּוּף אֶחָד, וְאִי עָבִיד יוֹתֵר וּבֵרַךְ עָלָיו הָוֵי בְּרָכָה לְבַטָּלָה (דִּבְרֵי עַצְמוֹ וּתְשׁוּבַת מַהֲרַ"ם שֶׁהֵבִיא הַבֵּית יוֹסֵף).

Partners in an alley must make an eruv in the courtyards. containing 1 paragraph: Those who partner in an alley must make an eruv in their courtyards, so that children will not forget the law of eruv—since children are not aware of what is done in the alley. Therefore, if they partnered in the alley with bread, one may rely on it and they need not make an eruv in the courtyards, since children recognize bread. Some say that if each courtyard did not make an eruv for itself, one may not rely on the partnership. However, when each courtyard made an eruv for itself and afterward they partnered in the alley but did not make an eruv through the openings between them, they are permitted to use the courtyards in the alley through the openings between them, for one may rely on the partnership in place of an eruv. And if they made an eruv through the openings between them but did not partner in the alley, the courtyards are permitted to use the alley, for one may rely on the eruv that the courtyards made through the openings in place of partnership. Rama: Some say one may rely on partnership in place of eruv even if they only partnered with wine, and similarly one may rely on eruv in place of partnership. Above in siman 366 section 6 I wrote that our practice is initially to make only one partnership with flour. The reason is that our eruv, where each resident of the courtyard contributes to the partnership, constitutes both eruv and partnership together, and initially one should not do more. The requirement for both partnership and eruv was in Talmudic times, when courtyard residents did not contribute to the partnership; rather, the courtyard made an eruv together and one member contributed to the partnership. But in such a case everyone agrees that one only makes one partnership, and if one does more and recites a blessing on it, it is a blessing in vain.