Sahih al-Bukhari, Volume 4, Book 56, Hadith 823 (USC-MSA) ⓘ
Narrated Abu Bakra: Once the Prophet 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 " .
also referenced under: Book 61, Hadith 133 (In-Book) & Hadith 3629 (DarusSalam)