Musnad Ahmad 941:42

Ya'la ibn 'Ubayd narrated to us, al-A'mash narrated to us, from Abu Wa'il, who said: It was said to Usamah: "Will you not speak to Uthman?" He said: "You think that I do not speak to him unless you hear me. Indeed, I speak to him between myself and him, without initiating a matter that I would not like to be the first to initiate. By Allah, I will not say to a man: 'You are the best of people,' even if he is an amir, after I heard the Messenger of Allah (ﷺ) say..." They said: "And what did you hear him say?" He said: "I heard him say: 'A man will be brought on the Day of Resurrection and cast into the Fire, and his intestines will spill out into the Fire. He will revolve therein as a donkey revolves around its millstone. The people of the Fire will gather around him and say: "O so-and-so, what is the matter with you? What has happened to you? Did you not use to command us to do good and forbid us from doing evil?" He will say: "I used to command you to do good but not do it myself, and I used to forbid you from doing evil but do it myself."'"