From Sahih Muslim (Hadith 3088):
Ibn Abbas (Allah be pleased with them) reported that Allah's Apostle (ﷺ) made al-Fadl sit behind him (on the camel back) from the place (where the two prayers) are combined (Muzdalifa). Ibn Abbas (Allah be pleased with them) also informed that Allah's Apostle (ﷺ) did not stop pronouncing Talbiya till he threw pebbles at Jamrat al-'Aqaba
Reference: Muslim 3088