In Book Five, Section 122 of the Masnavi, Rumi introduces the concept of hunger (jū') not merely as physical deprivation, but as the supreme remedy for spiritual and physical ailments, calling it the 'king of medicines' (sultān-i dārūhā). He explains that hunger serves as a transformative lens: it renders the unpleasant pleasant by cultivating appreciation and spiritual capacity, whereas a state of satiety or overindulgence deadens perception, causing even the most pleasant things to be rejected. This teaching underscores a core Sufi principle that voluntary restraint and abstinence are essential for purifying the soul and preparing the seeker to receive divine sustenance.