Musannaf Ibn Abi Shayba 3:12

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Al-A’mash narrated to us, from Ibrahim, from Al-Aswad, who said: I heard Umar saying when he opened the prayer: "Glory be to You, O Allah, and with Your praise, and blessed is Your name, and exalted is Your majesty, and there is no god other than You."