Reference for Bava Kamma 132:15

שינוי מעשה מאי טעמא התם מעיקרא עצים השתא כלים שינוי השם נמי מעיקרא קרו ליה משכא והשתא אברזין

— He replied:<span class="x" onmousemove="('comment',' R. Joseph to Abaye. ');">²⁷</span> We are dealing here with a case where for example he had already trimmed the stolen skins [so that some change in substance was effected].<span class="x" onmousemove="('comment',' On account of which the ownership was transferred. ');">²⁸</span>

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