It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: By Him in Whose hand is the soul of Muhammad (peace and blessings be upon him), the breath of a fasting person is more pleasant to Allah than the fragrance of musk. Allah Almighty says: My servant leaves his food, drink, and desires for My sake; therefore, fasting is for Me, and I Myself will give its reward. And apart from fasting, the reward for every good deed is from ten to seven hundred times.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 10693