Reference for Bekhorot 105:15

אי הכי מאחר שאינו קרב אמאי קדוש

[And I draw an analogy thus]: from the place from which you can bring up the tithe of grain<span class="x" onmousemove="('comment',' The tithing of grain is only practised in Palestine as it is a duty connected with the (Palestinian) soil.');">⁹</span>

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