Musannaf Ibn Abi Shayba 3:27

Abu Bakr narrated to us, he said: Abu Mu'awiyah narrated to us, from al-A'mash, from Ibrahim, from al-Aswad, who said: When Umar would begin the prayer, he would raise his voice so that we could hear him: "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."