Reference for Chullin 227:46

מה לאחותו גדולה שלא נכנסה עמו לדיר להתעשר

then the case of 'the older sister' argues otherwise.<span class="x" onmousemove="('comment',' For it also may be slaughtered with the kid on the same day and nevertheless it is forbidden to cook the kid in its milk.');">²⁰</span>

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