Al-Hasan ؓ most closely resembles the Messenger of Allah ﷺ in the chest and head, and Al-Husain ؓ most closely resembles the Prophet ﷺ in what is lower than that.
الْحَسَنُ أَشْبَهُ النَّاسِ بِرَسُولِ اللهِ ﷺ مَا بَيْنَ الصَّدْرِ إِلَى الرَّأْسِ وَالْحُسَيْنُ أَشْبَهُ النَّاسِ بِالنَّبِيِّ ﷺ مَا كَانَ أَسْفَلَ مِنْ ذَلِكَ
said: "Al-Hasan is greater in resemblance to the Messenger of Allah ﷺ with regards to what is between the chest and the head, and Al-Husain is greater in resemblance to the Messenger of Allah ﷺ with regards to what is below that."
الْحَسَنُ أَشْبَهُ بِرَسُولِ اللَّهِ ﷺ مَا بَيْنَ الصَّدْرِ إِلَى الرَّأْسِ وَالْحُسَيْنُ أَشْبَهُ بِالنَّبِيِّ ﷺ مَا كَانَ أَسْفَلَ مِنْ ذَلِكَ هَذَا حَدِيثٌ حَسَنٌ غَرِيبٌ
ʿAli ؓ said: al-Hasan most resembles the Messenger of Allah ﷺ between the navel and the head, and al-Husain most resembles him in what is lower than that.
عَلِيٌّ الْحَسَنُ أَشْبَهُ بِرَسُولِ اللهِ ﷺ مَا بَيْنَ الصَّدْرِ إِلَى الرَّأْسِ وَالْحُسَيْنُ أَشْبَهُ مَا أَسْفَلَ مِنْ ذَلِكَ
Al-Hasan ؓ most closely resembles the Messenger of Allah ﷺ in the chest and head, and Al-Husain ؓ most closely resembles the Prophet ﷺ in what is lower than that. (Using translation from Aḥmad 774)
«الْحَسَنُ أَشْبَهُ النَّاسِ بِرَسُولِ اللَّهِ ﷺ مَا بَيْنَ الصَّدْرِ إِلَى الرَّأْسِ وَالْحُسَيْنُ أَشْبَهُ النَّاسِ بِرَسُولِ اللَّهِ ﷺ مَا كَانَ أَسْفَلَ مِنْ ذَلِكَ»
"عَنْ عَلىٍّ قَالَ: الحَسَنُ أَشْبَهَ رَسُولَ الله ﷺ مَا بَيْنَ الصَّدْرِ إِلَى الرَّأسِ، وَالحُسَيْنُ أَشْبَهَ رسُول الله ﷺ مَا كَانَ أَسْفَلَ مِنْ ذَلِكَ".