Musnad Ahmad 33:908

Ya'qub narrated to us, my father narrated to us, from Ibn Ishaq, 'Asim ibn 'Umar ibn Qatadah narrated to me, from 'Abd al-Rahman ibn Jabir ibn 'Abd Allah, from Jabir ibn 'Abd Allah, who said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, say when the companions of Uhud were mentioned: "By Allah, I wish that I had been left behind with my companions at the side of the mountain," meaning the foot of the mountain.