Musannaf Ibn Abi Shayba 3:1745

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: ‘Ikrimah ibn ‘Ammar al-Yamami informed us, from Damdam ibn Jaws (Jubayr), from ‘Abdullah ibn Hanzalah ibn al-Rahib, he said: ‘Umar ibn al-Khattab led us in prayer, and he forgot to recite in the first rak’ah. When he stood for the second rak’ah, he recited the Opening of the Book (al-Fatihah) twice and two surahs. When he finished the prayer, he performed two prostrations (sujud).