Musannaf Ibn Abi Shayba 3:51

Hushaym narrated to us, from al-Zuhri, from Salim, from Ibn Umar, that the Prophet (peace and blessings of Allah be upon him) used to raise his hands when he began [the prayer], and when he bowed, and when he raised his head [from bowing], and he would not exceed his ears with them.