Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said: On the night of Muzdalifah, the Messenger of Allah (peace and blessings be upon him) sent us ahead with the young boys of Banu Abd al-Muttalib, and he (peace and blessings be upon him) began tapping our thighs, saying: "O my little sons, do not stone (the Jamrah) before the sun has risen."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9564