Musnad Ahmad 1153:560

Abu al-Yaman narrated to us, he said: Shu'ayb informed us, from al-Zuhri, he said: 'Urwah ibn al-Zubayr informed me, that 'Aishah, the wife of the Prophet, may Allah bless him and grant him peace, said: The Prophet, may Allah bless him and grant him peace, said: "There is no calamity that befalls a Muslim, except that Allah, the Almighty and Majestic, expiates [sins] from him by it, even the thorn that pricks him."