Reference for Bekhorot 52:27

תנהו לי שאוכלנו מותר

Thou shalt not delay to offer of the fullness of thy harvest and of the outflow of thy presses.<span class="x" onmousemove="('comment',' And next to this verse is another 'Likewise . . with thine oxen'. Here also we make a comparison as follows. Just as the fulness of thy harvest, i.e., the first-fruits, ripen on Passover and are brought to the Temple on Pentecost fifty days later, similarly the firstling of oxen, i.e., large cattle, must be looked after for a period of fifty days.');">¹⁵</span>

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