Musnad Ahmad 909
It was narrated that ‘Abd Khair al-Hamdani said:
I heard `Ali (رضي الله عنهما) say on the minbar: Shall I not tell you of the best of this ummah after its Prophet? Then he mentioned Abu Bakr. Then he said: Shall I not tell you of the second one? Then he mentioned `Umar (رضي الله عنهما). Then he said: If I wished, I could tell you of the third one, And he kept quiet. We thought that he meant himself. I [the narrator] said: Did you hear him say that? He said: Yes, by the Lord of the Ka`bah, otherwise may they [his ears] go deaf.
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ عَوْنٍ، حَدَّثَنَا مُبَارَكُ بْنُ سَعِيدٍ، أَخُو سُفْيَانَ عَنْ أَبِيهِ، عَنْ حَبِيبِ بْنِ أَبِي ثَابِتٍ، عَنْ عَبْدِ خَيْرٍ الْهَمْدَانِيِّ، قَالَ سَمِعْتُ عَلِيًّا، رَضِيَ اللَّهُ عَنْهُ يَقُولُ عَلَى الْمِنْبَرِ أَلَا أُخْبِرُكُمْ بِخَيْرِ هَذِهِ الْأُمَّةِ بَعْدَ نَبِيِّهَا قَالَ فَذَكَرَ أَبَا بَكْرٍ ثُمَّ قَالَ أَلَا أُخْبِرُكُمْ بِالثَّانِي قَالَ فَذَكَرَ عُمَرَ رَضِيَ اللَّهُ عَنْهُ ثُمَّ قَالَ لَوْ شِئْتُ لَأَنْبَأْتُكُمْ بِالثَّالِثِ قَالَ وَسَكَتَ فَرَأَيْنَا أَنَّهُ يَعْنِي نَفْسَهُ فَقُلْتُ أَنْتَ سَمِعْتَهُ يَقُولُ هَذَا قَالَ نَعَمْ وَرَبِّ الْكَعْبَةِ وَإِلَّا صُمَّتَا‏.‏