Sahih Bukhari Volume 2, Book 26, Hadith Number 807.
Narated By Salim : Ibn ‘Umar used to do Rami of the Jamrat-ud-Dunya (the Jamra near to the Khaif mosque) with seven small stones and used to recite Takbir on throwing every pebble. He then would go ahead till he reached the level ground where he would stand facing the Qibla for a long time to invoke (Allah) while raising his hands (while invoking). Then he would do Rami of the Jamrat-ul-Wusta (middle Jamra) and then he would go to the left towards the middle ground, where he would stand facing the Qibla. He would remain standing there for a long period to invoke (Allah) while raising his hands, and would stand there for a long period. Then he would do Rami of the Jamrat-ul-Aqaba from the middle of the valley, but he would not stay by it, and then he would leave and say, “I saw the Prophet doing like this.”