Talmud for Eruvin 115:5

א"כ לימא קרא חמשים חמשים מאי חמשים בחמשים שמעת מינה תרתי:

One taught: Neither less because the measurements are increased,<span class="x" onmousemove="('comment',' A shorter rope is likely to be stretched and each unit of rope would consequently cover more cubits of ground than the standard number it represents. The Sabbath limits would in consequence be greater than the permitted distance.');">⁸</span> nor more because they are reduced.<span class="x" onmousemove="('comment',' A longer rope cannot be so well stretched and each unit of it would cover less ground than the standard number it represents. This would result in a loss in the Sabbath limits.');">⁹</span> R'Assi<span class="x" onmousemove="('comment',' Aruk, 'Ammi'.');">¹⁰</span>

Jerusalem Talmud Eruvin