Hadith 5048
أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، أَنْبَأَنَا عَبْدُ الرَّزَّاقِ، قَالَ أَنْبَأَنَا مَعْمَرٌ، عَنْ أَيُّوبَ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم رَأَى صَبِيًّا حَلَقَ بَعْضَ رَأْسِهِ وَتَرَكَ بَعْضَ فَنَهَى عَنْ ذَلِكَ وَقَالَ " احْلِقُوهُ كُلَّهُ أَوِ اتْرُكُوهُ كُلَّهُ " .
It was narrated from Ibn 'Umar that :
The Prophet [SAW] saw a boy, part of whose head had been shaven and part had been left. He forbade that and said: "Shave all of it, or leave all of it."
Reference : Sunan an-Nasa'i 5048
In-book reference : Book 48, Hadith 9