Mishkat al-Masabih 41
‘Uthman said that when the Prophet died some of his companions were so grieved that they almost began to harbour doubts. Remarking that he was one of them, ‘Uthman said:
While I was sitting ‘Umar passed me and gave me a salutation, but I did not notice it. ‘Umar complained to Abu Bakr, and the two of them came forward and gave me a salutation; then Abu Bakr asked, “What induced you to refrain from returning the salutation of your brother ‘Umar?” I replied, “I did no such thing.” ‘Umar retorted, “Yes, I swear by God, you did.” I said, “I swear by God that I did not notice you passing me or giving me a salutation.” Abu Bakr then said, “‘Uthman is speaking the truth. Something must have distracted you.” On my replying that it had, he asked me what it was, and I said, “God has taken His Prophet before we asked him wherein this affair provides salvation.” Abu Bakr said that he had asked him about that, so I rose and went to him and said to him, “You for whom I would give my father and mother as ransom are most worthy of it.” Abu Bakr then told me that he had asked, “Messenger of God, wherein does this affair provide salvation?” to which God’s messenger replied, “If anyone accepts from me the confession which I proposed to my paternal uncle 1 and he rejected, it will be salvation for him.” 

Ahmad transmitted it. 1 Abu Talib, the uncle who gave protection in Makkah, but did not accept his religion.
عَنْ عُثْمَانَ بْنِ عَفَّانَ رَضِيَ اللَّهُ عَنْهُ قَالَ: إِنَّ رِجَالًا مِنْ أَصْحَابِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ حِينَ تُوُفِّيَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ حَزِنُوا عَلَيْهِ حَتَّى كَادَ بَعْضُهُمْ يُوَسْوِسُ قَالَ عُثْمَان وَكنت مِنْهُم فَبينا أَنا جَالس فِي ظلّ أَطَم من الْآطَام مر عَليّ عمر رَضِي الله عَنهُ فَسلم عَليّ فَلم أشعر أَنه مر وَلَا سلم فَانْطَلق عمر حَتَّى دخل على أبي بكر رَضِي الله عَنهُ فَقَالَ لَهُ مَا يُعْجِبك أَنِّي مَرَرْت على عُثْمَان فَسلمت عَلَيْهِ فَلم يرد عَليّ السَّلَام وَأَقْبل هُوَ وَأَبُو بكر فِي وِلَايَةَ أَبِي بَكْرٍ رَضِيَ اللَّهُ عَنْهُ حَتَّى سلما عَليّ جَمِيعًا ثمَّ قَالَ أَبُو بكر جَاءَنِي أَخُوك عمر فَذكر أَنه مر عَلَيْك فَسلم فَلم ترد عَلَيْهِ السَّلَام فَمَا الَّذِي حملك على ذَلِك قَالَ قُلْتُ مَا فَعَلْتُ فَقَالَ عُمَرُ بَلَى وَاللَّهِ لقد فعلت وَلكنهَا عبيتكم يَا بني أُميَّة قَالَ قُلْتُ وَاللَّهِ مَا شَعَرْتُ أَنَّكَ مَرَرْتَ وَلَا سَلَّمْتَ قَالَ أَبُو بَكْرٍ صَدَقَ عُثْمَانُ وَقد شَغَلَكَ عَنْ ذَلِكَ أَمْرٌ فَقُلْتُ أَجْلَ قَالَ مَا هُوَ فَقَالَ عُثْمَان رَضِي الله عَنهُ توفى الله عز وَجل نَبِيَّهُ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَبْلَ أَنْ نَسْأَلَهُ عَنْ نَجَاةِ هَذَا الْأَمْرِ قَالَ أَبُو بكر قد سَأَلته عَن ذَلِك قَالَ فَقُمْت إِلَيْهِ فَقلت لَهُ بِأَبِي أَنْتَ وَأُمِّي أَنْتَ أَحَقُّ بِهَا قَالَ أَبُو بَكْرٍ قُلْتُ يَا رَسُولَ اللَّهِ مَا نَجَاةُ هَذَا الْأَمْرِ فَقَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مَنْ قَبِلَ مِنِّي الْكَلِمَةَ الَّتِي عَرَضْتُ عَلَى عَمِّي فَرَدَّهَا فَهِيَ لَهُ نجاة. رَوَاهُ أَحْمد