مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 4423
Clothing
Combing the Hair - Section 1
وَعَنْ أَبِي هُرَيْرَةَ أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «إِنَّ الْيَهُودَ وَالنَّصَارَى لَا يَصبِغون فخالفوهم»
Abu Huraira reported the Prophet (ﷺ) as saying, “Jews and Christians do not dye [their beards], so act differently from them.” (Bukhari and Muslim.)
Mishkat al-Masabih, 4423مُتَّفَقٌ عَلَيْهِ (الألباني)