Reference for Bava Kamma 132:17
טעמא מפני תקנת השבים
Wherever there is no need for [finishing] work to be done, mental resolve<span class="x" onmousemove="('comment',' V. p. 384, n. 5. ');"><sup>31</sup></span> will render the article capable of becoming unclean, whereas where there is still need for [finishing] work to be done no mental resolve<span class="x" onmousemove="('comment',' V. p. 384, n. 5. ');"><sup>31</sup></span> will render it capable of becoming unclean, with the exception however, of a [dining] cover!<span class="x" onmousemove="('comment',' Since even without trimming the skins could be used as a cover. ');"><sup>32</sup></span> — Raba therefore said: This difficulty was pointed out by Rabbah to R. Joseph for twenty-two years<span class="x" onmousemove="('comment',' I.e., all the days when Rabbah was the head of the college at Pumbeditha; cf. Ber. 64a; Hor. 14a and Rashi Keth. 42b. ');"><sup>33</sup></span> without his obtaining any answer. It was only when R. Joseph occupied the seat as Head<span class="x" onmousemove="('comment',' In succession to Rabbah. ');"><sup>34</sup></span> that he explained it [by suggesting that] a change in name is equivalent [in the eye of the law] to a change in substance; for just as a change in substance has an effect because, for instance, what was previously timber is now utensils, so also a change in name should have an effect as what was previously called skin is now called [dining] cover.<span class="x" onmousemove="('comment',' Whereas mere Renunciation in the case of theft or robbery would not transfer ownership. ');"><sup>35</sup></span> But what about a beam where there is similarly a change in name as previously it was called a post and now ceiling, and we have nevertheless learnt that 'where a misappropriated beam has been built into a house, the owner will recover only its value, so as to make matters easier for repentant robbers'.<span class="x" onmousemove="('comment',' 'Ed. VII, 9. ');"><sup>36</sup></span> The reason is, to make matters easier for repentant robbers,