Musnad Abu Ya'la al-Mawsili 153:163

Abu Khaythama narrated to us, Uthman ibn Umar narrated to us, Yunus informed us, from al-Zuhri, that the Messenger of Allah (may Allah bless him and grant him peace) used to, when he threw the first Jamrah which is adjacent to the mosque—the mosque of Mina—throw it with seven pebbles, saying "Allahu Akbar" every time he threw a pebble. Then he would advance in front of it and stand facing the Qibla, raising his hands and supplicating, and he would prolong the standing. Then he would come to the second Jamrah and throw it with seven pebbles, saying "Allahu Akbar" every time he threw a pebble. Then he would descend to the left side, towards the valley, and stand facing the Qibla, raising his hands and supplicating. Then he would come to the Jamrah which is at al-Aqaba and throw it with seven pebbles, saying "Allahu Akbar" every time he threw a pebble. Then he would depart and not stand by it. Al-Zuhri said: I heard Salim narrating this from his father, from the Prophet (may Allah bless him and grant him peace), and Ibn Umar used to do that.