Musnad Ahmad 27:632

Isma'il ibn Ibrahim narrated to us, Ma'mar informed us, from al-Zuhri, from Salim ibn 'Abd Allah, from his father, who said: I saw the Messenger of Allah (peace and blessings of Allah be upon him) raising his hands when he entered into the prayer, when he bowed, and when he raised his head from bowing, and he would not do that in the prostration.