Musnad Ahmad 32:1316

Abdullah ibn al-Walid narrated to us, Sufyan narrated to us, from Khalid al-Hadhdha’, from Abu Na’amah al-Hanafi, from Anas, who said: "The Messenger of Allah (peace and blessings of Allah be upon him), Abu Bakr, and Umar would not recite," meaning: they would not recite aloud.