Musnad Ahmad 77
It was narrated that Ibn 'Abbas said:
When the Messenger of Allah (ﷺ) died and Abu Bakr was appointed as caliph, al-'Abbas disputed with ‘Ali concerning some things that the Messenger of Allah: had left behind. Abu Bakr said: It is something that the Messenger of Allah (ﷺ) left the way it is and I am not going to introduce any changes to it. When 'Umar was appointed as caliph, they referred the dispute to him and he said: It is something that Abu Bakr did not change and I am not going to change it. When 'Uthman was appointed as caliph, they referred the dispute to him and ‘Uthman remained quiet and lowered his head. Ibn 'Abbas said: I was afraid that he (‘Uthman) would take it back so I struck al-'Abbas between his shoulders and said: O my father, I insist that you give it to 'Ali. So he gave it to him.
حَدَّثَنَا يَحْيَى بْنُ حَمَّادٍ، حَدَّثَنَا أَبُو عَوَانَةَ، عَنِ الْأَعْمَشِ، عَنْ إِسْمَاعِيلَ بْنِ رَجَاءٍ، عَنْ عُمَيْرٍ، مَوْلَى الْعَبَّاسِ عَنِ ابْنِ عَبَّاسٍ، قَالَ لَمَّا قُبِضَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ وَاسْتُخْلِفَ أَبُو بَكْرٍ خَاصَمَ الْعَبَّاسُ عَلِيًّا فِي أَشْيَاءَ تَرَكَهَا رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ أَبُو بَكْرٍ رَضِيَ اللَّهُ عَنْهُ شَيْءٌ تَرَكَهُ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَلَمْ يُحَرِّكْهُ فَلَا أُحَرِّكُهُ فَلَمَّا اسْتُخْلِفَ عُمَرُ اخْتَصَمَا إِلَيْهِ فَقَالَ شَيْءٌ لَمْ يُحَرِّكْهُ أَبُو بَكْرٍ فَلَسْتُ أُحَرِّكُهُ قَالَ فَلَمَّا اسْتُخْلِفَ عُثْمَانُ رَضِيَ اللَّهُ عَنْهُ اخْتَصَمَا إِلَيْهِ قَالَ فَأَسْكَتَ عُثْمَانُ وَنَكَسَ رَأْسَهُ قَالَ ابْنُ عَبَّاسٍ فَخَشِيتُ أَنْ يَأْخُذَهُ فَضَرَبْتُ بِيَدِي بَيْنَ كَتِفَيْ الْعَبَّاسِ فَقُلْتُ يَا أَبَتِ أَقْسَمْتُ عَلَيْكَ إِلَّا سَلَّمْتَهُ لِعَلِيٍّ قَالَ فَسَلَّمَهُ لَهُ‏.‏