The prophet (peace and blessings be upon him) has said: “God says fasting is for Me, and I am the reward thereof.”
Hadhrat ‘Ali Hujwairi (may God sanctify his secret), commented in Kashful Mahjub (Unveling the Veiled): “What can be a greater reward than Allah himself.”
Commentary of Kash (in English edition): “The exoteric meaning of this Hadith is that those who fast to please God, are rewarded by God Himself. But the explanation is hardly tenable since it is God who rewards all good deeds. How can fasting be an exception? The real meaning as interpreted by the Sufis which is quite feasible, is that God Himself is the reward of those who fast for His sake. In other words, one gains God’s nearness and union by fasting, more than any other deed of worship. The Sufi shaikhs have said: ‘Fasting is one half of the spiritual journey to God.’ This is what the author (Ali Hujwairi) means by saying: “What can be a greater reward than Allah Himself.”