439. Amīr al-mu’minīn, peace be upon him, said: The whole of asceticism is confined between two expressions of the Qur’ān. Allāh, the Glorified says : “Lest distress you yourselves for what escapes you, and be overjoyous for what He has granted you” (Qur’ān, 57:23). Whoever does not grieve over what he misses and does not revel over what comes to him acquires asceticism from both its sides.