Sunan Abi Dawud, Hadith 4172

Narrated Al-Bara' : The Messenger of Allah had hair which reached the lobes of his ears.

حَدَّثَنَا حَفْصُ بْنُ عُمَرَ، حَدَّثَنَا شُعْبَةُ، عَنْ أَبِي إِسْحَاقَ، عَنِ الْبَرَاءِ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم لَهُ شَعْرٌ يَبْلُغُ شَحْمَةَ أُذُنَيْهِ ‏.‏

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also referenced under: Hadith 4184 (DarusSalam)