The Gemara in Nedarim (15a) says that an oath not to sleep for three days is considered to be a shevuas shav, a vain oath. It is not physically possible to stay awake for three days.

Zevachim 54Jan 6, 20116 min

Sleeping Duty

Before I started attending an early-morning daf yomi shiur, in my ignorance I envisioned that many attendees sleep through most of the shiur.

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Oath Not to Sleep for Three Days – Vows and Oaths in the Gemara | Daf Yomi Insights