Musnad Ahmad 7:34

Aswad ibn Amir narrated to us, Jarir narrated to us, he said: I heard al-Hasan say: Zubayr ibn al-Awwam said: "This verse was revealed while we were numerous with the Messenger of Allah, may Allah bless him and grant him peace: 'And fear a trial which will not strike those who have wronged among you exclusively' [al-Anfal: 25]." So we began to say: What is this trial? And we did not perceive that it would occur where it occurred. End of the hadith of Zubayr ibn al-Awwam, may Allah be pleased with him.