Reference for Bekhorot 66:5

דכיון דאיכא רווחא להקדש שרי לה

here also then, since there is a benefit for the Sanctuary, let the Rabbis permit its flaying? - Said R'Mari the son of R'Kahana: What benefit he obtains through selling the skin [at a high price], he loses by spoiling the flesh.<span class="x" onmousemove="('comment',' Cutting away some of the flesh together with the skin.');">⁴</span>

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