Musnad Abu Ya'la al-Mawsili 106:27

Ahmad ibn Ibrahim al-Dawraqi narrated to us, Bahz narrated to us, Shu'bah narrated to us, al-Hakam ibn 'Utaybah informed me, he said: 'Abd al-Rahman ibn Abi Layla narrated to me, narrating from al-Bara', he said: The bowing of the Messenger of Allah (may Allah bless him and grant him peace), and when he raised his head from the bowing, and when he prostrated, and between the two prostrations, were nearly equal.