Sahih Bukhari
Oneness, Uniqueness of Allah (Tawheed)
Volume: 009 / Book Number: 093 / Hadith Number: 584
Narrated Abu Huraira:
The Prophet said, "Allah said: The Fast is for Me and I will give the reward for it, as he (the one who observes the fast) leaves his sexual desire, food and drink for My Sake. Fasting is a screen (from Hell) and there are two pleasures for a fasting person, one at the time of breaking his fast, and the other at the time when he will meet his Lord. And the smell of the mouth of a fasting person is better in Allah's Sight than the smell of musk." (See Hadith No. 128, Vol. 3).