Editing Masekhet Shabbos (section)

== Measuring on Shabbat ==
The Gemara in '''Masechet Shabbat''' relates:<blockquote>"Ulla came to the house of the Reish Galuta, and saw Rabbah bar Rav Huna sitting in a tub of water measuring it. He said to him, 'The Rabbis permitted measuring for a mitzvah, but did they permit measuring not for a mitzvah?' He replied, 'I am merely occupied casually.'"</blockquote>Regarding this Gemara, the Rebbe said that one can ask a "klatz kashya" (obvious question). Although this is not the typical learning style in yeshivas, since "all your deeds should be for the sake of Heaven," how could Rabbah bar Rav Huna conduct himself in such a way - sitting on Shabbat in a tub full of water and explain it as "merely being occupied"?

And if you say he did it for the sake of Heaven, he could have answered this to Ulla, who himself said that measuring for a mitzvah was permitted by Chazal.

The Rebbe explains that this matter of measuring is not inherently forbidden as a weekday activity, but rather it is a rabbinic decree. And although the Alter Rebbe rules that it falls under weekday activities, this doesn't mean it is inherently a weekday activity, but rather that this was the rabbinic decree, to prevent people from treating Shabbat lightly in the future.