Musnad Ahmad 30:2016

Hawdha narrated to us, 'Awf ibn Abi Jamila narrated to us, from Muhammad, from Abu Hurayra, from the Prophet, peace and blessings of Allah be upon him, who said: "The change in the breath of the fasting person is more pleasant to Allah than the scent of musk." He said: "Your Lord, Mighty and Majestic, says: 'My servant has abandoned his desire, his food, and his drink for the sake of seeking My pleasure. Fasting is for Me, and I shall reward for it.'"