وَعَنِ ابْنِ عَبَّاسٍ قَالَ: كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يُحِبُّ مُوَافَقَةَ أَهْلِ الْكِتَابِ فِيمَا لَمْ يُؤْمَرْ فِيهِ وَكَانَ أَهْلُ الْكِتَابِ يَسْدُلُونَ أَشْعَارَهُمْ وَكَانَ الْمُشْرِكُونَ يَفْرِقُونَ رؤوسهم فَسَدَلَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ نَاصِيَتَهُ ثمَّ فرق بعدُ

Ibn ‘Abbas said the Prophet liked to do the same as the People of the Book in matters about which he had received no command. The People of the Book used to let their hair hang down and the polytheists used to part their hair, so the Prophet let his forelock hang down, but afterwards he parted it. (Bukhari and Muslim.)