Musnad Ahmad 3:137

Abdullah narrated to us, Muhammad ibn Abi Bakr narrated to me, Zuhayr ibn Ishaq narrated to us, Dawud ibn Abi Hind narrated to us, from Ziyad ibn Abdullah, from Umm Hilal bint Waki’, from Na’ilah bint al-Farafisah, the wife of Uthman ibn Affan, who said: The Commander of the Faithful, Uthman, became drowsy and dozed off. Then he woke up and said: "The people will surely kill me." I said: "No, if Allah wills, it will not reach that point. Your subjects have sought to appease you." He said: "I saw the Messenger of Allah, peace and blessings of Allah be upon him, in my sleep, along with Abu Bakr and Umar, and they said: 'Break your fast with us tonight.'"