Musannaf Ibn Abi Shayba 37:599

Zayd ibn al-Hubab narrated to us, he said: Muhammad ibn Suqah narrated to me, he said: Mundhir al-Thawri narrated to me, he said: We were with Muhammad ibn al-Hanafiyyah, and some of the people spoke ill of Uthman. He said, "Desist." We said to him, "Your father used to revile Uthman." He said, "He did not revile him. If he were to have reviled him one day, he would have reviled him the day I came to him and the tax collectors came to him. He said, 'The best of the Book of Allah is regarding the tax collectors, so take it to Uthman.' So I took it and went with it to him. He said, 'We have no need for it.' I came to him [my father] and informed him, and he said, 'Put it back in its place.' If he were to have reviled him one day, he would have reviled him that day."