Musnad Ahmad 937:284

Abdullah narrated to us, Muhammad ibn Mahdi al-Ayli narrated to us, Abu Dawud narrated to us, Mahdi ibn Maymun narrated to us, from Wasil, the freed slave of Abu Uyaynah, from Yahya ibn Aqil, from Yahya ibn Ya'mar, from Abu al-Aswad al-Du'ali, who said: "I have seen the companions of the Prophet, may Allah bless him and grant him peace, and I have not seen anyone like Abu Dharr." End of the hadith of Abu Dharr, may Allah be pleased with him.