סימן צה סעיף ז
כֵּיצַד עוֹשִׂין אֶת הָעֵרוּב. לוֹקֵחַ פַּת כְּדֵי מְזוֹן שְׁתֵּי סְעוּדּוֹת אוֹ לִפְתָּן (כְּגוֹן בְּצָלִים אוֹ צְנוֹן וְכַדּוֹמֶה), שֶׁיֶּשׁ בּוֹ שִׁעוּר לְאָכְלוֹ עִם פַּת, שֶׁהִיא כְּדֵי מְזוֹן שְׁתֵּי סְעוּדּוֹת חוּץ מִן הַמֶּלַח וּמִן הַמַּיִם שֶׁאֵין מְעָרְבִין בָּהֶם, וְהוֹלֵךְ אֶל הַמָּקוֹם שֶׁהוּא רוֹצֶה לְהַנִּיחוֹ, וּמְבָרֵךְ בָּרוּךְ אַתָּה ה' אֱלֹקֵינוּ מֶלֶךְ הָעוֹלָם אֲשֶׁר קִדְּשָׁנוּ בְּמִצְוֹתָיו וְצִוָּנוּ עַל מִצְוַת עֵרוּב. וְאוֹמֵר, בָּזֶה הָעֵרוּב, יְהֵא מֻתָּר לִי לֵילֵךְ מִמָּקוֹם זֶה אַלְפַּיִם אַמָּה לְכָל רוּחַ, וְחוֹזֵר לְבֵיתוֹ. יָכוֹל לְהַנִּיחַ עֵרוּב אֶחָד לְכַמָּה שַׁבָּתוֹת, וּבִלְבַד שֶׁיַּנִּיחֶנּוּ בְּמָּקוֹם הַמִּשְׁתַּמֵּר, שֶׁלֹּא יְהֵא נֶאֱבָד אוֹ נִתְקַלְקֵל (שפ"ו ת"ח תט"ו תט"ז).
How do you make this eiruv?18The main stipulation for acquiring shevisah is to be there in person at twilight until dark. The Rabanan said you may make an eiruv by having a prescribed amount of food in that place at the onset of Shabbos. [Mishnah Berurah 409: 28] You take bread enough for two19See Chapter 94: 8. meals, or relish, like onions or radish, or something similar, enough to eat with bread for two meals, except for salt and water20There are other things you may not use for an eiruv, such as spices, raw beans etc., and anything that is marginally edible. [Shulchan Aruch 409: 7, 386: 5] with which you cannot make an eiruv, and go to the place where you want to put the eiruv; and you should say: Baruch atah A-donoy Elokeinu melech ha'olam asher kiddeshanu bemitzvosav vetzivanu al mitzvas eiruv. [Blessed are You, Hashem, our God King of the Universe, Who has sanctified us with His commandments and has commanded us concerning the mitzvah of eiruv.] Then you should say:21If you did not say this, it is not a valid eiruv. [Magein Avraham] If all you said was, “This should be an eiruv,” it is sufficient. [Chayei Adam] If you made an eiruv by being there from twilight until dark, you need not say anything. [Peri Megadim] "By means of this eiruv it shall be permissible for me to walk from this place two thousand amos in each direction," and then return home. You may place one eiruv for many Shabbosos, but you should put it in a safe place, so that it will not be lost or spoiled.22Shulchan Aruch 416: 1.
תנא דבי אליהו כל השונה הלכות בכל יום מובטח לו שהוא בן העולם הבא שנאמר הליכות עולם לו אל תקרי הליכות אלא הלכות (נדה ע"ג.)