Sunan Abi Dawud, Hadith 4171

Narrated Al-Bara' : I did not see any man with locks hanging down to shoulders in red robe more beautiful than the Messenger of Allah. Muhammad b. Sulaiman added: He had hair which touched his shoulders. Abu Dawud said: Isra'il also transmitted it in a similar way from Abu Ishaq saying: "(his hair) touched his shoulders". Shu'bah added: (His hair) reached the lobes of his ears.

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ، وَمُحَمَّدُ بْنُ سُلَيْمَانَ الأَنْبَارِيُّ، قَالاَ حَدَّثَنَا وَكِيعٌ، عَنْ سُفْيَانَ، عَنْ أَبِي إِسْحَاقَ، عَنِ الْبَرَاءِ، قَالَ مَا رَأَيْتُ مِنْ ذِي لِمَّةٍ أَحْسَنَ فِي حُلَّةٍ حَمْرَاءَ مِنْ رَسُولِ اللَّهِ صلى الله عليه وسلم زَادَ مُحَمَّدُ بْنُ سُلَيْمَانَ لَهُ شَعْرٌ يَضْرِبُ مَنْكِبَيْهِ ‏.‏ قَالَ أَبُو دَاوُدَ وَكَذَا رَوَاهُ إِسْرَائِيلُ عَنْ أَبِي إِسْحَاقَ قَالَ يَضْرِبُ مَنْكِبَيْهِ وَقَالَ شُعْبَةُ يَبْلُغُ شَحْمَةَ أُذُنَيْهِ ‏.‏

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also referenced under: Hadith 4183 (DarusSalam)