In Chapter 13, Poem 20 of Attar's Mokhtar Nameh, the spiritual journey is depicted as a harsh desert that requires immense endurance. The seeker's heart constantly suffers and 'turns to blood,' emphasizing the agonizing nature of divine love. Attar suggests that to survive and progress on this arduous path, a seeker must possess a 'heart of stone'—a metaphor for unwavering resilience, immense emotional fortitude, and the ability to endure profound spiritual suffering without breaking.