Talmud for Eruvin 139:19
ואין שנים שעירבו נותנין רשותן לשנים שלא עירבו הא תו למה לי לא צריכא דבטיל ליה חד מינייהו לחבריה מהו דתימא לשתרי ליה קמ"ל כיון דבעידנא דבטיל לא הוו ליה שריותא בהא חצר לא
'Nor may two who joined in an 'erub present their shares to the two who did not join'. What need again was there for this ruling?<span class="x" onmousemove="('comment',' Which is implied in the preceding rulings.');"><sup>61</sup></span> - It was required in that case only where one of them<span class="x" onmousemove="('comment',' Of those who did not join in the 'erub.');"><sup>62</sup></span> renounced his share in favour of the other.<span class="x" onmousemove="('comment',' Of those who did not join in the 'erub.');"><sup>62</sup></span> As it might have been presumed that the, latter should be permitted the unrestricted use of this courtyard.<span class="x" onmousemove="('comment',' As is the case where all tenants presented their shares to one of their own number.');"><sup>63</sup></span>