Reference for Pesachim 57:1

דישראל נמי מישרא קא שרי ואי ר' יוסי הגלילי אפי' תוך זמנו נמי מישרא קא שרי בהנאה

even that of an Israelite is indeed permitted.<span class="x" onmousemove="('comment',' For general use, after its time.');">¹</span> while if [it is] R'Jose the Galilean, even during its time it indeed permitted for [general] use? - Said R'Aha B'Jacob: In truth it is R'Judah, and he learns se'or [leaven] of 'eating' from se'or of seeing':<span class="x" onmousemove="('comment',' I.e., he learns the prohibition of eating se'or from that of seeing se'or.');">²</span>

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