Superiority of Fasting (Saum)
106) Narrated Abu Huraira Allah's Messenger said: Allah said: Every good deed performed by son of Adam is a credit for him but fasting is exclusively Mine and I give reward for it. Fasting is a shield against sins. Therefore, when any of you is fasting he should neither indulge in obscene language nor raise the voice. If anyone abuses him or quarrels with him, he should say: I am fasting. By Him in Whose Hand is Muhammad's soul! The smell coming out of the mouth of a person fasting is more pleasant to Allah than the smell of musk. And he who fasts has two occasions of joy. One is when he breaks the fast, and the second is when he meets his Lord.
(This Hadith is sound and reported by Bukhari and Muslim).