Reference for Eruvin 76:19

א"ל מי סברת דאזיל ואמר מידי דאזיל ושתיק ויתיב

It is at the beginning of the day<span class="x" onmousemove="('comment',' For which the 'erub is required, i.e., [he Sabbath.');">²⁸</span> that its validity is acquired, and on the Sabbath one may well make preparations for the Sabbath itself.

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