Reference for Bekhorot 33:34

זיל בתר אימיה והאי לאו נדמה הוא ומר סבר

Because Scripture says: And one [he-goat],<span class="x" onmousemove="('comment',' Num. XXVIII, 15. We infer from this that the goat must belong to the family of goats all time.');">¹⁹</span>

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