Hajj (Pilgrimage)
حَدَّثَنَا أَبُو الْيَمَانِ، أَخْبَرَنَا شُعَيْبُ بْنُ أَبِي حَمْزَةَ، قَالَ نَافِعٌ كَانَ ابْنُ عُمَرَ ـ رضى الله عنهما ـ يَقُولُ حَلَقَ رَسُولُ اللَّهِ صلى الله عليه وسلم فِي حَجَّتِهِ.Narrated Ibn `Umar:Allah's Messenger (ﷺ) (got) his head shaved after performing his Hajj
From Sahih al-Bukhari, whose reports the scholars accept as authentic.