Ali bin Ma'bd bin Shdad علي بن معبد بن شداد · The Book of Hajj

"We entered upon Jabir bin 'Abdullah and I said: 'Tell me about the Hajj of the Prophet. He said: 'The Messenger of Allah stoned the Jamart which is by the tree, with seven pebbles, saying the Takbir with eeach pebble - pebbles that were the size of data stones or fingertips. And he threw them for the bottom of the valley, then he went to the place of sacrifice in Mina."'