Bukhari Collection: ::Book Number 9:: Hadith # 218
Narrated Abu Wail:Someone said to Usama, "Will you not talk to this (Uthman)?" Usama said, "I talked to him (secretly) without being the first man to open an evil door. I will never tell a ruler who rules over two men or more that he is good after I heard Allah's Apostle saying, 'A man will be brought and put in Hell (Fire) and he will circumambulate (go around and round) in Hell (Fire) like a donkey of a (flour) grinding mill, and all the people of Hell (Fire) will gather around him and will say to him, O so-and-so! Didn't you use to order others for good and forbid them from evil?' That man will say, 'I used to order others to do good but I myself never used to do it, and I used to forbid others from evil while I myself used to do evil.' "