Musnad Ahmad 27:1570

Abu al-Yaman narrated to us, Shu'ayb narrated to us, from al-Zuhri, Salim ibn 'Abd Allah informed me, that 'Abd Allah ibn 'Umar said: I heard the Prophet, peace and blessings of Allah be upon him, saying: "People are only like a hundred camels; you will scarcely find a riding beast among them."