<b>And the whole earth was of one language (Gen. 11:1).</b> May it please our master to teach us why a house with an <i>eruv</i><sup class="footnote-marker">27</sup><i class="footnote">A legal fiction which establishes the continuity of a community so as to make certain types of activities permissible on the Sabbath within the designated area.</i> has an <i>eruv.</i> Thus did our masters instruct us:<sup class="footnote-marker">28</sup><i class="footnote">Y. Eruvin 6:7, Buber Tanhuma 22.</i> R. Jacob the son of R. Aha asked R. Abahu whether it was necessary to place an <i>eruv</i> in an area having a common courtyard if others had previously placed one there, and he replied: The School of Shammai states that he must do so, while the School of Hillel maintains that it is not necessary. The law is in accordance with the opinion of the School of Hillel. R. Joshua the son of Levi said: They instituted the practice of placing an <i>eruv</i> in an area with a common courtyard only to advance the cause of peace. How does it achieve that goal? If a woman sends her son to deposit the <i>eruv</i> and her neighbor is kind to him and kisses him, his mother will undoubtedly say to herself: Truly she must love him, and she in turn will become fond of the woman who loves her son, no matter how she felt toward her previously. Hence, you find that peace prevails between them because of the <i>eruv.</i> The Holy One, blessed be He, said: I established peace in My world, but these wicked men arise to foment conflict in it. Whence do we know this? From the fact that they fought against the Holy One, blessed be He, as is related in the chapter <i>And the whole earth was of one language and one kind of words</i> (Gen. 11:1).