Musnad Abu Ya'la al-Mawsili 109:306

Ibn Numayr narrated to us, Mahadir narrated to us, al-A'mash narrated to us, from Abu Sufyan, from Jabir, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "No believing man or believing woman, and no Muslim man or Muslim woman, falls ill, except that Allah removes their sins by means of it."