The Rites of Hajj (Kitab Al-Manasik Wa'l-Hajj)
Dawud :: Book 10 : Hadith 1946
Narrated A man from the Companions of the Prophet:
AbdurRahman ibn Mu'adh said that he heard a man from the Companions of the Prophet (peace_be_upon_him) say: The Prophet (peace_be_upon_him) addressed the people at Mina and he made them stay in their dwellings. He then said: The Muhajirun (Emigrants) should stay here, and he made a sign to the right side of the qiblah, and the Ansar (the Helpers) here, and he made a sign to the left side of the qiblah; the people should stay around them.