Musnad Ahmad 30:3360

Muhammad ibn Abdullah ibn al-Zubayr narrated to us, Ibn Abi Dhi’b narrated to us, from Muhammad ibn Amr ibn Ata, from Muhammad ibn Abd al-Rahman ibn Thawban, from Abu Hurayrah, that the Messenger of Allah, peace and blessings of Allah be upon him, when he stood in prayer, would raise his hands extended.