יֵשׁ דְּבָרִים שֶׁהֵן אֲסוּרִין בְּשַׁבָּת אַף עַל פִּי שֶׁאֵינָם דּוֹמִין לִמְלָאכָה וְאֵינָם מְבִיאִין לִידֵי מְלָאכָה. וּמִפְּנֵי מָה נֶאֶסְרוּ מִשּׁוּם שֶׁנֶּאֱמַר (ישעיה נח יג) "אִם תָּשִׁיב מִשַּׁבָּת רַגְלֶךָ עֲשׂוֹת חֲפָצֶיךָ בְּיוֹם קָדְשִׁי" וְנֶאֱמַר (ישעיה נח יג) "וְכִבַּדְתּוֹ מֵעֲשׂוֹת דְּרָכֶיךָ מִמְּצוֹא חֶפְצְךָ וְדַבֵּר דָּבָר". לְפִיכָךְ אָסוּר לְאָדָם לְהַלֵּךְ בַּחֲפָצָיו בְּשַׁבָּת וַאֲפִלּוּ לְדַבֵּר בָּהֶן כְּגוֹן שֶׁיְּדַבֵּר עִם שֻׁתָּפוֹ מַה יִּמְכֹּר לְמָחָר אוֹ מַה יִּקְנֶה אוֹ הֵיאַךְ יִבְנֶה בַּיִת זֶה וּבְאֵי זֶה סְחוֹרָה יֵלֵךְ לְמָקוֹם פְּלוֹנִי. כָּל זֶה וְכַיּוֹצֵא בּוֹ אָסוּר שֶׁנֶּאֱמַר וְדַבֵּר דָּבָר דִּבּוּר אָסוּר הִרְהוּר מֻתָּר:
There are things that are forbidden on the Sabbath even though they are not similar to creative labor and they do not bring [one] [to doing] creative labor. And because of what were [they] forbidden? Because it was said "If because of the Sabbath you refrain your feet from acting on your concerns on My holy day" (Isaiah 58:13) and it was said, "And you shall honor it, [refraining] from doing your ways, from finding your desires and from speaking about a matter" (Isaiah 58:13). Therefore it is forbidden for a person to go [after] one's concerns on the Sabbath, and even to speak about them. For example, if one would speak with one's business partner [about] what he will sell the following day or what he will buy or how he will build this house or regarding which merchandise will go to a certain person's place. All of this and similar cases are forbidden, as it says: "speaking about a matter" - speaking is forbidden; thinking is permitted.
