Sunan Abi Dawud 4193
سنن أبي داود#4193Sahihحَدَّثَنَا أَحْمَدُ بْنُ حَنْبَلٍ، حَدَّثَنَا عُثْمَانُ بْنُ عُثْمَانَ، - قَالَ أَحْمَدُ كَانَ رَجُلاً صَالِحًا - قَالَ أَخْبَرَنَا عُمَرُ بْنُ نَافِعٍ عَنْ أَبِيهِ عَنِ ابْنِ عُمَرَ قَالَ نَهَى رَسُولُ اللَّهِ صلى الله عليه وسلم عَنِ الْقَزَعِ وَالْقَزَعُ أَنْ يُحْلَقَ رَأْسُ الصَّبِيِّ فَيُتْرَكَ بَعْضُ شَعْرِهِ .
Narrated Ibn 'Umar:The Messenger of Allah (ﷺ) forbade qaza'. Qaza' means having part of a boy's head shaved and leaving part unshaven
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Zubair Ali ZaiSahih Bukhari (5920) Sahih Muslim (2120)
In-book reference: 35:35