Musnad Ahmad 30:3088

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from Sulayman, from Dhakwan, from Abu Hurayrah, from the Prophet, peace and blessings of Allah be upon him, who said: "Every good deed the son of Adam performs is ten good deeds, up to seven hundred good deeds. Allah, the Mighty and Majestic, says: 'Except for fasting, for it is Mine, and I reward for it. He leaves his food for My sake, his drink for My sake, and his desire for My sake. So it is Mine, and I reward for it. And 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 his Lord." "And the change in the odor of the fasting person's mouth, when he abstains from food, is more pleasant to Allah than the scent of musk."