Sulayman bin Amr narrates from his mother (may Allah be pleased with her): I saw the Prophet (peace and blessings be upon him) stoning the Jamrah from the middle of the valley while he (peace and blessings be upon him) was riding, saying the takbir with each pebble, and a man behind him (peace and blessings be upon him) was shielding him. I asked about that man, and they said: It is al-Fadl bin Abbas (may Allah be pleased with him). When the people crowded together, the Prophet (peace and blessings be upon him) said: "O people, do not kill one another, and when you stone the Jamrah, throw small pebbles."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9555