Musannaf Ibn Abi Shayba 3:15

Abu Bakr narrated to us, he said: Abu Khalid al-Ahmar narrated to us, from Isma'il bin Abi Khalid, from Hakim bin Jabir, that 'Umar, when he would begin the prayer, used to say: "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."