Reference for Pesachim 102:8

א"ל רב ספרא לרבי אבא כגון אנן דידעינן בקביעא דירחא

[No:] they will indeed say, 'How many unemployed are there in the market place!'<span class="x" onmousemove="('comment',' Raba explains the Mishnah thus: IF A MAN GOES FROM A PLACE WHERE THEY DO NOT WORK TO A PLACE WHERE THEY WORK . . WE IMPOSE UPON HIM THE RESTRICTION OF THE PLACE WHENCE HE HAS DEPARTED. For the general principle that a man MUST NOT ACT DIFFERENTLY from the rest of the people was only ON ACCOUNT OF THE QUARRELS, whereas here we have no fear.');">¹²</span> R'Safra said to R'Abba:<span class="x" onmousemove="('comment',' Var. lec. Raba.');">¹³</span> For instance I,<span class="x" onmousemove="('comment',' [So Tosaf. and MS. M., cur. edd. 'we'.]');">¹⁴</span> who know [the art] of fixing the New Moon,<span class="x" onmousemove="('comment',' By Biblical law Festivals are holy on the first and the seventh days only (Pentecost one day altogether) . But owing to uncertainty in early time about the exact day of New Moon, i.e., when the month began, it became a binding practice in the Diaspora to observe two days instead of one, and this remained binding even when New Moon was ascertained by mathematical calculation, which obviated all doubt.');">¹⁵</span>

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