Mishkat al-Masabih 29 Excellent Qualities and Description of the Prophet كتاب الفضائل والشمائل 73

وَعَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ قَالَ: كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَشَدَّ حَيَاءً مِنَ الْعَذْرَاءِ فِي خِدْرِهَا فَإِذَا رَأَى شَيْئًا يَكْرَهُهُ عَرَفْنَاهُ فِي وَجْهِهِ. مُتَّفَقٌ عَلَيْهِ

Abu Sa’id al-Khudri said: The Prophet was more modest than a virgin in her apartment, and when he saw anything of which he disapproved we could recognise the fact in his face. (Bukhari and Muslim.)