Sahih Muslim 7339
In-book no 62حَدَّثَنَا عَبْدُ بْنُ حُمَيْدٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، أَخْبَرَنَا مَعْمَرٌ، عَنِ الزُّهْرِيِّ، بِهَذَا الإِسْنَادِ وَقَالَ مَرَّ بِرَجُلٍ مِنَ الأَنْصَارِ يَعِظُ أَخَاهُ .
Zuhri has narrated this hadith with the addition of these words: He (the Holy Prophet) happened to pass by a mass of Ansar who was instructing his brother (about modesty).