In Chapter 10, Poem 40 of Mokhtar Nameh, Attar of Nishapur defines death not as the end of life, but as the ultimate spiritual liberation. He employs the metaphor of the physical body as a "cage" and the soul as a "nightingale" yearning for freedom. This mystical death requires transcending both the material and immaterial realms (the "two worlds"), completely severing ties with the ego, and ultimately achieving union with the Divine.