In Book Two, Section 21 of the Masnavi, Rumi explores the relationship between outward speech and the inner self during the king's examination of the first slave. Finding the slave to be articulate and intelligent, Rumi introduces the famous concept that "Man is hidden beneath his tongue." He employs the metaphor of the tongue as a curtain draped over the doorway of the soul; when speech moves the curtain, the true nature of the individual—whether harboring valuable treasures or harmful traits—is exposed. This narrative serves to illustrate that verbal expression is the primary indicator of one's spiritual and intellectual state.