Musnad Abu Ya'la al-Mawsili 1:10

Abu Khaythama narrated to us, Ya’qub ibn Ibrahim narrated to us, my father narrated to us, from Salih, from Ibn Shihab: A man from the Ansar, from the people of jurisprudence, who was not accused [of lying], narrated to me that he heard Uthman ibn Affan narrating: That men from the companions of the Messenger of Allah (may Allah bless him and grant him peace) were saddened for him when the Messenger of Allah (may Allah bless him and grant him peace) passed away, until some of them were almost driven to madness. Uthman said: "I was among them." "While I was sitting in the shade of a fortress, Umar ibn al-Khattab passed by me and greeted me, but I did not perceive that he had passed or greeted. Umar went on until he entered upon Abu Bakr and said: 'Are you not amazed? I passed by Uthman and greeted him, but he did not return the greeting to me.' So Abu Bakr and Umar came during the caliphate of Abu Bakr until they arrived and both greeted [me]. Then Abu Bakr said: 'Your brother Umar came to me and claimed that he passed by you and greeted you, but you did not return the greeting to him. So what caused you to do that?' I said: 'I did not do that.' Umar said: 'Yes, you did, but it is your arrogance, O Banu Umayya.'" Uthman said: "I said: 'By Allah, I did not perceive that you passed or greeted.' Abu Bakr said: 'Uthman speaks the truth, but a matter has preoccupied you from that.' I said: 'Yes.' He said: 'And what is it?' Uthman said: 'I said: Allah took His Prophet (may Allah bless him and grant him peace) before I could ask him about the salvation of this matter.' Abu Bakr said: 'I asked him about that.'" Uthman said: "I said: 'May my father and mother be sacrificed for you, you are more entitled to it.' Abu Bakr said: 'I said: O Messenger of Allah, what is the salvation of this matter? The Messenger of Allah (may Allah bless him and grant him peace) said: Whoever accepts from me the word which I offered to my uncle, and he rejected it, then it is salvation for him.'"