Mattityahu 24:20-22

Orthodox Jewish Bible

²⁰ But offer tefillos that your escape may not be in winter or on Shabbos.

²¹ For then will be Tzarah Gedolah (Great Tribulation) such as has not been from Reshit HaOlam (Beginning of the World) until now nor will it by any means happen again.

²² And if those days were not cut short, kol basar (all flesh) would not be saved. But, on account of the Kadoshim, the Bechirim (Chosen Ones), those days will be cut short.