Musnad Ahmad 1153:2086

Uthman ibn Umar narrated to us, he said: Abd al-Hamid ibn Ja'far informed me, he said: My father informed me, from Hamzah ibn Abdullah ibn al-Zubayr, and Muhammad ibn Bakr, he said: Abd al-Hamid ibn Ja'far informed us, he said: My father informed me, from Hamzah ibn Abdullah ibn al-Zubayr, from Aisha, that she heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "Nothing befalls the believer except that there is a reward for him in it, or an expiation, even for a misfortune or a thorn."