The Heart Knows Its Own Bitterness
"The Heart Knows Its Own Bitterness" (Hebrew: לֵב יוֹדֵעַ מָרַּת נַפְשׁוֹ) is a sugya (passage) in the Babylonian Talmud's tractate Yoma, which discusses when a person may be exempt from fasting on Yom Kippur, the Day of Atonement. The sugya hinges on the interpretation of a Biblical verse.
Source: Wikipedia — The Heart Knows Its Own Bitterness (CC BY-SA 4.0)