Musannaf Ibn Abi Shayba 27:610

Muhammad ibn Bishr narrated to us, he said: Mis'ar narrated to us, from 'Amr ibn Murrah, from Abu al-Bakhtari, who said: 'Ali was asked about 'Ammar. He said: "A believing, righteous man. If you mention him, he remembers [Allah]. Faith has entered into his hearing, his sight, and whatever Allah willed of his body."