Musnad Abu Ya'la al-Mawsili 42:283

Zuhayr narrated to us, Isma'il ibn 'Ulayyah narrated to us, from Muhammad ibn Ishaq, from Muhammad ibn 'Amr ibn 'Ata', from 'Ata' ibn Yasar, from Abu Sa'id al-Khudri, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "The believer is not afflicted with fatigue, nor illness, nor sadness, nor harm—even the worry that concerns him—except that Allah expiates some of his sins."