Musnad Abu Ya'la al-Mawsili 147:24

Uthman ibn Abi Shaybah narrated to us, Abu Dawud al-Hafari, Umar ibn Sa'd, narrated to us, from Sufyan al-Thawri, from Khalid, from Abu Na'amah, from Anas, who said: The Prophet, peace and blessings of Allah be upon him, and Abu Bakr, and Umar, did not recite "In the name of Allah, the Most Gracious, the Most Merciful."