According to Ali, fasting was not a mere formality or a ritual; it was an exercise for the purification of the soul. Because of his constant fasting, Ali earned the epithets of "Qa'im-ul-Lail" (Praying most of the night without sleep), and "Sa'im-un-Nahar", (Fasting mostly during the day). Ali held that hunger sharpens the intelligence, and improves the mind and health. Hunger involves home affliction for the body, but it illumines the heart, purifies the soul, and leads the spirit into the presence of God. One who cultivates his spiritual nature by means of hunger in order to devote himself entirely to God and detach himself from worldly ties is at a much higher level than the person who cultivates his body by means of gluttony and lust. Ali acted on the advice of the Holy Prophet, "Fast so that perchance your hearts may see God in this world". And verily, because of his fasting and other spiritual exercises, Ali did see God in this world. The Holy Prophet had enjoined, "When you fast, let your ear, your eye, your tongue, your hand, and your every limb fast." Ali followed this advice in letter as well as in spirit. By the discipline of fasting, Ali was able to subordinate the physical senses to spiritual requirements in such a way that they could respond only to what was pure and became dead to what was impure. Ali thus led a purified life.
