Musnad Ahmad 953
It was narrated that ‘Ali (رضي الله عنه) said:
When al-Hasan was born, the Messenger of Allah (ﷺ)  came and said: “Show me my son; what did you name him?` I said: I named him Harb [which means `war`]. He said: `Rather he is Hasan.” When al-Husain was born, he said: `Show me my son; what did you name him?` I said: I named him Harb, He said: `Rather he is Husain.” When the third one was born, the Prophet (ﷺ) said: `Show me my son; what did you name him?` I said: Harb, He said: “Rather. he is Muhassin.” Then he said: “I have named them after the fashion of the sons of Haroon, Shabbar and Shabeer and Mushabbir.”
حَدَّثَنَا حَجَّاجٌ، حَدَّثَنَا إِسْرَائِيلُ، عَنْ أَبِي إِسْحَاقَ، عَنْ هَانِئِ بْنِ هَانِئٍ، عَنْ عَلِيٍّ، رَضِيَ اللَّهُ عَنْهُ قَالَ لَمَّا وُلِدَ الْحَسَنُ جَاءَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ أَرُونِي ابْنِي مَا سَمَّيْتُمُوهُ قُلْتُ سَمَّيْتُهُ حَرْبًا قَالَ بَلْ هُوَ حَسَنٌ فَلَمَّا وُلِدَ الْحُسَيْنُ قَالَ أَرُونِي ابْنِي مَا سَمَّيْتُمُوهُ قُلْتُ سَمَّيْتُهُ حَرْبًا قَالَ بَلْ هُوَ حُسَيْنٌ فَلَمَّا وَلَدْتُ الثَّالِثَ جَاءَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ أَرُونِي ابْنِي مَا سَمَّيْتُمُوهُ قُلْتُ حَرْبًا قَالَ بَلْ هُوَ مُحَسِّنٌ ثُمَّ قَالَ سَمَّيْتُهُمْ بِأَسْمَاءِ وَلَدِ هَارُونَ شَبَّرُ وَشَبِيرُ وَمُشَبِّرُ‏.‏