Nedarim 90

מתני׳ <big><strong>השותפין</strong></big> שנדרו הנאה זה מזה אסורין ליכנס לחצר ר"א בן יעקב אומר זה נכנס לתוך שלו וזה נכנס לתוך שלו

<b><i>MISHNAH</i></b>. IF [TWO] JOINT OWNERS MADE A VOW NOT TO BENEFIT FROM ONE ANOTHER, THEY MAY NOT ENTER THE COURTYARD.<span class="x" onmousemove="('comment',' Which belongs to both. ');">¹</span> R. ELIEZER B. JACOB SAID: EACH ENTERS INTO HIS OWN.<span class="x" onmousemove="('comment',' He maintains that it is as though it had been stipulated when jointly acquiring the property, that it should belong to each partner separately for his entering therein. Consequently, when he enters, he is not benefiting from the other. The Sages do not accept this view. ');">²</span>