Musnad Abu Ya'la al-Mawsili 153:43

Abu Khaythama narrated to us, Ya'qub narrated to us, from my father, from Ibn Shihab, from Salim, from his father, who said: I heard the Messenger of Allah, may Allah bless him and grant him peace, say: "People are only like a hundred camels; you will hardly find a riding beast among them."