Language:
كتاب المناقب
61
Virtues and Merits of the Prophet (pbuh) and his Companions
(25)
Chapter: The signs of Prophethood in Islam
(25)
باب عَلاَمَاتِ النُّبُوَّةِ فِي الإِسْلاَمِ
Sahih al-Bukhari 3629

Narrated Abu Bakra:

Once the Prophet (ﷺ) brought out Al-Hasan and took him up the pulpit along with him and said, "This son of mine is a Saiyid (i.e. chief) and I hope that Allah will help him bring about reconciliation between two Muslim groups."

حَدَّثَنِي عَبْدُ اللَّهِ بْنُ مُحَمَّدٍ، حَدَّثَنَا يَحْيَى بْنُ آدَمَ، حَدَّثَنَا حُسَيْنٌ الْجُعْفِيُّ، عَنْ أَبِي مُوسَى، عَنِ الْحَسَنِ، عَنْ أَبِي بَكْرَةَ ـ رضى الله عنه ـ أَخْرَجَ النَّبِيُّ صلى الله عليه وسلم ذَاتَ يَوْمٍ الْحَسَنَ فَصَعِدَ بِهِ عَلَى الْمِنْبَرِ، فَقَالَ ‏ "‏ ابْنِي هَذَا سَيِّدٌ، وَلَعَلَّ اللَّهَ أَنْ يُصْلِحَ بِهِ بَيْنَ فِئَتَيْنِ مِنَ الْمُسْلِمِينَ ‏"‏‏.‏
Reference : Sahih al-Bukhari 3629
In-book reference : Book 61, Hadith 133
USC-MSA web (English) reference : Vol. 4, Book 56, Hadith 823
  (deprecated numbering scheme)