Musnad Ahmad 5:630

'Abd al-Razzaq narrated to us, Ibn 'Uyaynah informed us, from Muhammad ibn Suqah, from Mundhir al-Thawri, from Muhammad ibn 'Ali, who said: Some people came to 'Ali and complained about the tax collectors of 'Uthman. He said: My father said to me, "Take this document to 'Uthman and say to him: 'The people have complained about your tax collectors, and this is the command of the Messenger of Allah, peace and blessings of Allah be upon him, regarding charity (zakat). So order them to follow it.'" He said: So I went to 'Uthman and mentioned that to him. He said: "If he were to remind 'Uthman of anything, he would have reminded him on that day"—meaning—with evil.