If Ali had spoken anything bad about 'Uthman then he would have ...

Hadith 4:343

Narrated Ibn Al-Hanafiya:

If Ali had spoken anything bad about 'Uthman then he would have mentioned the day when some persons came to him and complained about the Zakat officials of 'Uthman. 'Ali then said to me, "Go to 'Uthman and say to him, 'This document contains the regulations of spending the Sadaqa of Allah's Apostle so order your Zakat officials to act accordingly." I took the document to 'Uthman. 'Uthman said, "Take it away, for we are not in need of it." I returned to 'Ali with it and informed him of that. He said, "Put it whence you took it."

Hanafiya who said, "My father sent me saying, 'Take this letter to 'Uthman for it contains the orders of the Prophet concerning the Sadaqa.' "