Sahih Muslim | Book 42 | Chapter 9

Narrated by Shaqiq
Shaqiq reported that it was said to Usama b. Zaid: Why don't you visit 'Uthman and talk to him? Thereupon he said: Do you think that I have not talked to him but that I have made you hear? By Allah. I have talked to him (about things) concerning me and him and I did not like to divulge those things about which I had to take the initiative and I do not say to my ruler: "You are the best among people," after I heard Allah's Messenger (may peace be upon him) as saying: A man will be brought on the Day of Resurrection and thrown in Hell-Fire and his intestines will pour forth in Hell and he will go round along with them, as an ass goes round the mill-stone. The denizens of Hell would gather round him and say: O, so and so, what has happened to you? Were you not enjoining us to do what was reputable and forbid us to do what was disreputable? He will say: Of course, it is so; I used to enjoin (upon people) to do what was reputable but did not practise that myself. I had been forbidding people to do what was disreputable, but practised it myself.
Narrated by Abu Wa'il
Abu Wa'il reported: I was in the company of Usama b. Zaid that a person said: What prevents you to visit Uthman and talk to him for what he does? The rest of the hadith is the same.