Uthman bin Ghyath عثمان بن غياث · The Book of the Commencement of the Prayer

"The Messenger of Allah (ﷺ) led us in prayer, and we did not hear him recite: In the Name of Allah, the Most Gracious, the Most Merciful. And Abu Bakr and Umar led us in prayer and we did not hear it from them either."