Musnad Ahmad 482:103

Hashim ibn al-Qasim narrated to us, Layth narrated to us, Qabath ibn Razin narrated to us, from Ali ibn Rabah, from Uqbah ibn Amir al-Juhani, who said: The Messenger of Allah, peace and blessings of Allah be upon him, came out to us while we were studying the Quran. He said: "Learn the Quran and acquire it"—Qabath said: "And I do not know it except that he said"—"and sing it [recite it with a melodious voice], for it is more prone to escaping than camels in their hobbles."