Musnad Ahmad 26:539

Yahya narrated to us, from al-Mas'udi, Jami' ibn Shaddad narrated to me, he said: I heard 'Abd al-Rahman ibn Yazid, he said: I saw 'Abdullah enter the interior of the valley, and he placed the Jamrah to his right side, and he faced the House (the Ka'bah), then he threw at it seven pebbles, saying the Takbir after every pebble. Then he said: "This, by the One besides whom there is no god, is the station of the one upon whom Surah al-Baqarah was revealed."