Musnad Ahmad 1059
It was narrated that ‘Abd Khair said:
I heard ‘Ali (رضي الله عنه) say: Allah took His Prophet in the best way any Prophet was ever taken, then Abu Bakr (رضي الله عنه) was appointed as his successor and he did what the Messenger of Allah (ﷺ) had done and followed the Sunnah of his Prophet, and `Umar                  (رضي الله عنه) was appointed and did likewise.
حَدَّثَنَا عَبْد اللَّهِ، حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا ابْنُ نُمَيْرٍ، عَنْ عَبْدِ الْمَلِكِ بْنِ سَلْعٍ، عَنْ عَبْدِ خَيْرٍ، قَالَ سَمِعْتُ عَلِيًّا، رَضِيَ اللَّهُ عَنْهُ يَقُولُ قَبَضَ اللَّهُ نَبِيَّهُ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَلَى خَيْرِ مَا قُبِضَ عَلَيْهِ نَبِيٌّ مِنْ الْأَنْبِيَاءِ عَلَيْهِمْ السَّلَام ثُمَّ اسْتُخْلِفَ أَبُو بَكْرٍ رَضِيَ اللَّهُ عَنْهُ فَعَمِلَ بِعَمَلِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ وَسُنَّةِ نَبِيِّهِ وَعُمَرُ رَضِيَ اللَّهُ عَنْهُ كَذَلِكَ‏.‏