Musannaf Ibn Abi Shayba 27:522

Muhammad ibn Bishr narrated to us, he said: Ibn al-Mubarak narrated to us, from Ibn Ishaq, he said: Yahya ibn 'Abbad narrated to me, from his father, from 'Abdullah ibn al-Zubayr, from al-Zubayr, he said: I heard the Messenger of Allah, may Allah bless him and grant him peace, say on that day—meaning the day of Uhud—"Talha has made it obligatory," meaning on the day of Uhud.