Reference for Bekhorot 42:2

מחוסר זמן נכנס לדיר להתעשר

R'Simeon the son of Judah reported in the name of R'Simeon: An animal, though immature,<span class="x" onmousemove="('comment',' I.e., too early for sacrifice, before the expiration of the seven days after birth.');">¹</span>

Jastrow

Jastrow

Jastrow