Latest / Matmonim: Daf Yomi by Rabbi David Lapin
Beitzah 35b Distraction on Shabbat - טירחה בשבת
Shabbat is about the mind. Yom Tov is about the body. Hard physical labor is permitted on Shabbat. It is mental distraction from Kedushat Shabbat (the sanctity of Shabbat) that is forbidden. Yom Tov is different.
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