In Attar's 'The Tale of the Man Who Turned to Stone in the Mountains of China', the petrification of the man and his tears serves as an allegory for spiritual knowledge (علم, 'ilm) that has stagnated. The poem explains that knowledge turns to stone due to the grief caused by the 'ambitionless' (بی‌همتان) and the 'ungrateful' (کافرنعمتان). This illustrates the Sufi principle that true gnosis must be actively practiced with high spiritual aspiration and gratitude; otherwise, it loses its guiding brilliance (the 'jewel') and solidifies into a source of perpetual sorrow and regret.