Musnad Abu Ya'la al-Mawsili 131:12

Abu Bahz al-Saqr ibn Abd al-Rahman, the son of the daughter of Malik ibn Mighwal, narrated to us, saying: Abdullah ibn Idris narrated to us, from al-Mukhtar ibn Fulful, from Anas, who said: The Prophet, may Allah bless him and grant him peace, came and entered a garden. Then someone came and knocked on the door. He said: "O Anas, rise and open for him, and give him glad tidings of Paradise, and give him glad tidings of the Caliphate after me." I said: "O Messenger of Allah, shall I inform him?" He said: "Inform him." So I went out, and it was Abu Bakr. I said: "Receive glad tidings of Paradise, and receive glad tidings of the Caliphate after the Messenger of Allah, may Allah bless him and grant him peace." Then someone came and knocked on the door. He said: "O Anas, rise and open for him, and give him glad tidings of Paradise, and give him glad tidings of the Caliphate after Abu Bakr." I said: "O Messenger of Allah, shall I inform him?" He said: "Inform him." I went out, and it was Umar. I said to him: "Receive glad tidings of Paradise, and receive glad tidings of the Caliphate after Abu Bakr." He said: Then someone came and knocked on the door. He said: "O Anas, rise and open for him, and give him glad tidings of Paradise, and give him glad tidings of the Caliphate after Umar, and that he will be killed." I went out, and it was Uthman. I said to him: "Receive glad tidings of Paradise, and of the Caliphate after Umar, and that you will be killed." He said: So he entered upon the Prophet, may Allah bless him and grant him peace, and said: "O Messenger of Allah, why? By Allah, I have not sung, nor have I wished for anything, nor have I touched my private part since I pledged allegiance to you." He said: "It is as such, O Uthman."