Reference for Eruvin 179:9

רב אמר מותר לטלטל בכולו קשיא דרב אדרב התם לא מינכרא מחיצתא הכא מינכרא מחיצתא

Rab ruled: It is permissible to move objects through their areas,<span class="x" onmousemove="('comment',' Lit., 'in all of it'.');">³⁵</span> and Samuel ruled: Objects may be moved only within four cubits.<span class="x" onmousemove="('comment',' On the same roof according to the Rabbis or on two roofs (a portion of the four cubits on each) according to R. Meir.');">³⁶</span> As 'Rab ruled: It is permissible to move objects throughout their areas,<span class="x" onmousemove="('comment',' From which it follows that he adopts the principle of the upward extension of the walls under the roofs to form partitions around the roofs.');">³⁷</span> does not a contradiction arise between two rulings<span class="x" onmousemove="('comment',' Lit., 'a difficulty of that of rab on that'.');">³⁸</span> of Rab?<span class="x" onmousemove="('comment',' The one just cited and the ruling. Supra 89a, that on roofs of the same level, according to the Rabbis, objects 'may be moved only within four cubits', from which it is obvious that he does not recognize the principle of the upward extension of walls.');">³⁹</span>

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