صحيح مسلم

Abu Huraira (Allah be pleased with him) reported Allah's Messenger (ﷺ) as saying: Every (good) deed of the son of Adam would be multiplied, a good deed receiving a tenfold to seven hundredfold reward. Allah, the Exalted and Majestic, has said: With the exception of fasting, for it is done for Me and I will give a reward for it, for one abandons his passion and food for My sake. There are two occasions of joy for one who fasts, joy when he breaks it, and joy when he meets his Lord, and the breath (of an observer of fast) is sweeter to Allah than the fragrance of musk.