عَنِ ابْنِ عَبَّاسٍ قَالَ: كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُصُّ أَوْ يَأْخُذُ مِنْ شَارِبِهِ وَكَانَ إِبْرَاهِيمُ خَلِيلُ الرَّحْمَنِ صَلَوَاتُ الرَّحْمَنِ عَلَيْهِ يَفْعَله. رَوَاهُ التِّرْمِذِيّ
Translation

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.