Musannaf Ibn Abi Shayba 22:151

Ibn Idris narrated to us, from al-A’mash, from Ibrahim, from Abdullah, who said: Mu’adh came to the Prophet, may Allah bless him and grant him peace, and said: "O Messenger of Allah, teach me to recite." The Messenger of Allah, may Allah bless him and grant him peace, said: "Teach him to recite." So I taught him what I had with me. Then he and I used to go back and forth to the Messenger of Allah, may Allah bless him and grant him peace, and Mu’adh would recite it. He was one of the teachers during the time of the Messenger of Allah, may Allah bless him and grant him peace.