Musannaf Ibn Abi Shaybah

Hazrat Salih bin Saeed, the muezzin, narrates: He says that I was with Hazrat Umar bin Abdul Aziz (may Allah have mercy on him) at the place of Suwaida. So I gave the call to prayer (adhan) for Isha and he performed the prayer, then went into the palace. After staying there for a short while, he came out again, prayed two rak'ahs like those of Duha, and then sat down with his knees raised (in the position of ihtiba). And he began to recite Surah Anfal. He (may Allah have mercy on him) kept repeating and reciting Surah Anfal continuously. Whenever he passed by a verse of warning, he would show humility, and whenever he passed by a verse of mercy, he would supplicate. This continued until I gave the call to prayer (adhan) for Fajr.