Musnad Ahmad 30:1991

Abu Nu'aym narrated to us, he said: Al-A'mash narrated to us, from Abu Salih, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Allah, the Mighty and Majestic, says: 'Fasting is for Me, and I reward for it. He leaves his food, his drink, and his desire for My sake. So fasting is a shield.'" "And for the fasting person there are two joys: a joy when he breaks his fast, and a joy when he meets Allah, the Mighty and Majestic." "And the change in the breath of his mouth is better to Allah than the scent of musk."