In Chapter 17, Poem 13 of Attar's Mokhtar Nameh, the poet explores the profound state of spiritual detachment and the painful necessity of suppressing mystical secrets. The imagery of wiping the 'slate of the heart' clean signifies complete detachment from both the material and spiritual realms ('the two worlds'). Furthermore, the poet describes swallowing unspoken words despite intense suffering—symbolized by having one's head treated as a ball—which highlights the heavy burden of unutterable spiritual truths.