Musannaf Ibn Abi Shayba 22:17

Abu Usama narrated to us, from Awf, from Khulayd al-Asri, who said: When Salman came to us, we went to him so that he would recite the Quran to us. He said, "The Quran is Arabic, so have an Arab man recite it to you." So we had Zayd ibn Suhan recite it to us. Whenever he made a mistake, Salman would correct him, and whenever he got it right, he would say, "By Allah."