Talmud for Eruvin 139:17

או לאחד שלא עירב למה לי מהו דתימא הני מילי היכא דמקצתן עירבו ומקצתן לא עירבו אבל היכא דכולן לא עירבו ליקנסינהו כדי שלא תשתכח תורת עירוב קמ"ל

Or to one neighbour who did not prepare an 'erub'. What need was there for this ruling?<span class="x" onmousemove="('comment',' Which is implied in the previous ones.');">⁵⁴</span> _ It might have been presumed that those rulings<span class="x" onmousemove="('comment',' Enumerated previously, according to which such renunciation is permitted.');">⁵⁵</span> applied only where some of the tenants joined in an 'erub and only some did not, but that where all the tenants failed to join in an 'erub they should be penalized<span class="x" onmousemove="('comment',' By depriving them of the right to renunciation.');">⁵⁶</span> in order that the law of 'erub shall not be forgotten.<span class="x" onmousemove="('comment',' Were renunciation allowed, no 'erub would ever be prepared and the younger generation would in consequence remain ignorant of the institution of 'erub'.');">⁵⁷</span>

Jerusalem Talmud Eruvin