Musnad Ahmad 1215:0

Narrated to us by Muhammad ibn Ja’far, who said: Narrated to us Shu’bah, from ‘Amr ibn Murrah, who said: I heard Murrah al-Hamadani narrating from Umm Sulaym bint ‘Amr ibn al-Ahwas, that she performed the Hajj with the Messenger of Allah (ﷺ). She said: I saw the Messenger of Allah (ﷺ) while he was at the Jamrah, and he was saying something, and the people were around him. Some were protecting him, and some were pushing him, so that he might reach the Jamrah. She said: I heard him say: "O people, do not kill one another. When you throw the pebbles, throw with pebbles the size of the fingertips."