Mishkat al-Masabih 22 Clothing كتاب اللباس 149

وَعَن أنسٍ قَالَ: كَانَتْ لِي ذُؤَابَةٌ فَقَالَتْ لِي أُمِّي: لَا أَجُزُّهَا كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَمُدُّهَا وَيَأْخُذُهَا. رَوَاهُ أَبُو دَاوُدَ

Anas said he had a hanging lock of hair and his mother told him not to cut it, for God’s messenger used to stretch it out and hold it. Abu Dawud transmitted it.