Musnad Ahmad 33:1029

Mu'awiyah—meaning Ibn 'Amr—narrated to us, Abu Ishaq—meaning al-Fazari—narrated to us, from al-A'mash, from Abu Sufyan, from Jabir, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "There is no Muslim man, nor Muslim woman, nor believing man, nor believing woman who falls ill with an illness, except that Allah removes from him some of his sins."