Musannaf Ibn Abi Shayba 3:48

Abu Bakr narrated to us, he said: Sufyan ibn ‘Uyaynah narrated to us, from al-Zuhri, from Salim, from his father, who said: I saw the Prophet, peace and blessings of Allah be upon him, raising his hands when he commenced the prayer, and when he bowed, and after he rose [from bowing]. And he would not raise his hands between the two prostrations.