Musnad Ahmad 1153:2017

Yazid narrated to us, he said: Ja'far ibn Burd informed us, from Umm Salim al-Rasibiyyah, she said: I heard Aisha saying: The Messenger of Allah, peace and blessings of Allah be upon him, said: "By the One in Whose hand is the soul of Muhammad, the change in the breath of the fasting person is more pleasant to Allah than the scent of musk."