Saying Allahu 'Akbar while stoning the three pillars at Mina
 

239. The Prophet (SAW) said:

اللهُ أَكْبرُ!

Allaahu 'Akbar 

Allah is the Most Great

with each pebble he threw at the three pillars. Then he went forward, stood facing the Qiblah and raised his hands and called upon Allah. That was after (stoning) the first and second pillar. As for the third, he stoned it and called out Allaahu 'Akbar with every pebble he threw, but when he was finished he left without standing at it (for supplications).

Reference: Al-Bukhari, cf. Al-Asqalani, Fathul-Bari 3/581, 3, 4, and Muslim