Musnad Ahmad — Hadith 24009/76

Abd al-Samad narrated to us, my father narrated to me, Abu Abdullah al-Shaqari narrated to us, Umar ibn Jabir narrated to me, from Abdullah ibn Badr, from Abdur Rahman ibn Ali, from his father, who said: I heard the Messenger of Allah, peace and blessings be upon him, say: "Indeed, Allah does not look at a man who does not straighten his back in his bowing and in his prostration."