Musannaf Ibn Abi Shayba 3:1408

Ibn ‘Ulayyah narrated to us, from Ayyub and Ibn Abi ‘Arubah, from Abu Ma‘shar, from Ibrahim, who said: Al-Aswad said: "That I should bite upon a live coal is more beloved to me than that I should recite behind the Imam, while I know that he is reciting."