Muhammad bin Abd al-Rahman bin Yazid (may Allah have mercy on him) reports from his father that he said: "I departed from Jam' with Abdullah (may Allah be pleased with him), and he kept saying the Talbiyah until he stoned Jamrat al-Aqabah. He went into the middle of the valley and said: O my nephew, hand me seven stones. So he threw seven pebbles, saying the takbir with each pebble, until when he finished he said: O Allah, make this an accepted Hajj and forgive the sins. Then he said: I saw the one (peace and blessings be upon him) upon whom Surah al-Baqarah was revealed doing it just like this."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9549