Sahih al-Bukhari #4170 · Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)

Sahih al-BukhariAl-Musaiyab
Sahih al-Bukhari · Book 64 · Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)
Sahih al-Bukhari · كتاب 64 · كتاب المغازي
I met Al-Bara bin 'Azib and said (to him). "May you live prosperously! You enjoyed the company of the Prophet (ﷺ) and gave him the Pledge of allegiance (of Al-Hudaibiya) under the Tree." On that, Al- Bara' said, "O my nephew! You do not know what we have done after him (i.e. his death)
حَدَّثَنِي أَحْمَدُ بْنُ إِشْكَابٍ، حَدَّثَنَا مُحَمَّدُ بْنُ فُضَيْلٍ، عَنِ الْعَلاَءِ بْنِ الْمُسَيَّبِ، عَنْ أَبِيهِ، قَالَ لَقِيتُ الْبَرَاءَ بْنَ عَازِبٍ ـ رضى الله
عنهما ـ فَقُلْتُ طُوبَى لَكَ صَحِبْتَ النَّبِيَّ صلى الله عليه وسلم وَبَايَعْتَهُ تَحْتَ الشَّجَرَةِ‏.‏ فَقَالَ يَا ابْنَ أَخِي إِنَّكَ لاَ تَدْرِي مَا أَحْدَثْنَا بَعْدَهُ‏.‏
Reference : Sahih al-Bukhari 4170In-book reference : Book 64, Hadith 212