Sahih al-Bukhari 1406

ʿAli said: He heard Hushaym. Husayn informed us, from Zayd ibn Wahb, who said: I passed through al-Rabadha and there was Abu Dharr (may Allah be pleased with him). I said to him, ‘What brought you to this place where you are staying?’ He said, ‘I was in Syria, and Muʿawiya and I disagreed about those who hoard gold and silver and do not spend it in Allah’s way. Muʿawiya said, “It was revealed concerning the People of the Book.” I said, “It was revealed concerning us and them.” We continued in disagreement over that, and he wrote to ʿUthman (may Allah be pleased with him), complaining of me. ʿUthman wrote to me, “Come to Medina.” I came there, and people gathered around me in such numbers that it was as though they had never seen me before. I mentioned that to ʿUthman, and he said to me, “If you wish, withdraw and stay nearby.” That is what brought me to this place. Even if they appointed an Abyssinian over me, I would hear and obey.’