Reference for Yoma 124:4

והשתא דרבי רחמנא שעיר שעיר שני שני שני למה לי חד למראה וחד לקומה וחד לדמים

which is inclusive [widens the scope]. Now the reason, then, is only that the Divine Law expressly includes it, but had the Divine Law not done so, one would have assumed that they are invalid.

Jastrow

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