Musannaf Ibn Abi Shayba 3:1232

Abu al-Ahwas narrated to us, from Abu Ishaq, from Abd al-Rahman ibn Yazid, who said: Abdullah led us in the final Isha prayer. He began [reciting] al-Anfal until he reached: "And know that Allah is your Protector; excellent is the Protector, and excellent is the Helper." He then bowed, and after that, he stood up and recited a surah in the second [rak'ah].