Musnad Ahmad 482:70

'Abdullah ibn Yazid narrated to us, Qubath ibn Razin al-Lakhmi narrated to us, he said: I heard 'Ali ibn Rabah al-Lakhmi saying: I heard 'Uqbah ibn 'Amir al-Juhani saying: We were sitting in the mosque reciting the Qur'an, and the Messenger of Allah (peace and blessings of Allah be upon him) entered. He greeted us, and we returned the greeting to him. Then he said: "Learn the Book of Allah and possess it" — Qubath said: And I think he said — "and sing it. For by the One in Whose hand is the soul of Muhammad, it is more prone to escape than the hobbled camel is from its tether."