In Jalal al-Din Rumi's Masnavi (Book Five, Section 125), the story of the cow on the green island serves as a spiritual allegory for human greed (tama'), anxiety over sustenance (rizq), and the lack of tawakkul (absolute trust in God). Despite years of experiencing God's daily renewal of pasture, the cow's existential dread at night prevents it from resting, causing it to lose its physical strength. This cycle illustrates how the ego (nafs) is imprisoned by temporal anxiety and material calculation, failing to recognize the unchanging nature of divine providence. Rumi uses this parable to urge seekers to transcend worldly anxiety by placing their complete reliance in the ultimate Sustainer.