Language:
كتاب الفتن
92  
Afflictions and the End of the World
(20)
Chapter: “This son of mine is a chief, and Allah may make peace between two groups of Muslims through him.”
(20)
بَابُ قَوْلِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ لِلْحَسَنِ بْنِ عَلِيٍّ: «إِنَّ ابْنِي هَذَا لَسَيِّدٌ وَلَعَلَّ اللَّهَ أَنْ يُصْلِحَ بِهِ بَيْنَ فِئَتَيْنِ مِنَ الْمُسْلِمِينَ»
Sahih al-Bukhari 7109

Narrated Al-Hasan Al-Basri:

When Al-Hasan bin `Ali moved with army units against Muawiya, `Amr bin AL-As said to Muawiya, "I see an army that will not retreat unless and until the opposing army retreats." Muawiya said, "(If the Muslims are killed) who will look after their children?" `Amr bin Al-As said: I (will look after them). On that, `Abdullah bin 'Amir and `Abdur-Rahman bin Samura said, "Let us meet Muawaiya and suggest peace." Al-Hasan Al-Basri added: No doubt, I heard that Abu Bakra said, "Once while the Prophet was addressing (the people), Al-Hasan (bin `Ali) came and the Prophet (ﷺ) said, 'This son of mine is a chief, and Allah may make peace between two groups of Muslims through him."

حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا سُفْيَانُ، حَدَّثَنَا إِسْرَائِيلُ أَبُو مُوسَى، وَلَقِيتُهُ، بِالْكُوفَةِ جَاءَ إِلَى ابْنِ شُبْرُمَةَ فَقَالَ أَدْخِلْنِي عَلَى عِيسَى فَأَعِظَهُ‏.‏ فَكَأَنَّ ابْنَ شُبْرُمَةَ خَافَ عَلَيْهِ فَلَمْ يَفْعَلْ‏.‏ قَالَ حَدَّثَنَا الْحَسَنُ قَالَ لَمَّا سَارَ الْحَسَنُ بْنُ عَلِيٍّ ـ رضى الله عنهما ـ إِلَى مُعَاوِيَةَ بِالْكَتَائِبِ‏.‏ قَالَ عَمْرُو بْنُ الْعَاصِ لِمُعَاوِيَةَ أَرَى كَتِيبَةً لاَ تُوَلِّي حَتَّى تُدْبِرَ أُخْرَاهَا‏.‏ قَالَ مُعَاوِيَةُ مَنْ لِذَرَارِيِّ الْمُسْلِمِينَ‏.‏ فَقَالَ أَنَا‏.‏ فَقَالَ عَبْدُ اللَّهِ بْنُ عَامِرٍ وَعَبْدُ الرَّحْمَنِ بْنُ سَمُرَةَ نَلْقَاهُ فَنَقُولُ لَهُ الصُّلْحَ‏.‏ قَالَ الْحَسَنُ وَلَقَدْ سَمِعْتُ أَبَا بَكْرَةَ قَالَ بَيْنَا النَّبِيُّ صلى الله عليه وسلم يَخْطُبُ جَاءَ الْحَسَنُ فَقَالَ النَّبِيُّ صلى الله عليه وسلم ‏ "‏ ابْنِي هَذَا سَيِّدٌ وَلَعَلَّ اللَّهَ أَنْ يُصْلِحَ بِهِ بَيْنَ فِئَتَيْنِ مِنَ الْمُسْلِمِينَ ‏"‏‏.‏
Reference : Sahih al-Bukhari 7109
In-book reference : Book 92, Hadith 56
USC-MSA web (English) reference : Vol. 9, Book 88, Hadith 225
  (deprecated numbering scheme)