Reference for Shabbat 250:14
מאי בין כך ובין כך אמר ר' אבא אמר רב כהנא
If so, he makes use of what is attached to the soil?<span class="x" onmousemove="('comment',' Even if tied before the Sabbath it is still that and is forbidden. ');"><sup>26</sup></span> — It is below three.<span class="x" onmousemove="('comment',' Handbreadths from the ground. Such may be used, v 'Erub. 99b. ');"><sup>27</sup></span> R. Ashi said: You may even say that it refers to a detached [branch]: it is a preventive measure, lest he cut (i.e., shorten] it.<span class="x" onmousemove="('comment',' On the Sabbath, if it is not fastened to the pitcher before. Hence even R. Simeon b. Gamaliel agrees. ');"><sup>28</sup></span> AS FOR THE STOPPER OF A SKYLIGHT, etc. Rabbah b. Bar Hanah said in R. Johanan's name: All agree that we may not make for the first time a temporary building on a Festival, whilst on the Sabbath it goes without saying. They differ only in respect of adding [to a building]: R. Eleazar maintaining. We may not add on a Festival, whilst on the Sabbath it goes without saying; whereas the Sages rule: We may add on the Sabbath, whilst it is superfluous to speak of a Festival. BUT THE SAGES MAINTAIN: IN BOTH CASES WE MAY CLOSE (THE SKYLIGHT] WITH IT. What does 'IN BOTH CASES' mean? — R. Abba said in R. Kahana's name: