The Messenger of Allah [SAW] said: "The Jews and the Christians do not dye their hair, so be different from them."  

عَنْ رَسُولِ اللَّهِ ﷺ قَالَ إِنَّ الْيَهُودَ وَالنَّصَارَى لاَ يَصْبُغُونَ فَخَالِفُوهُمْ  

"Abu Quhafah was brought to the Messenger of Allah [SAW] and his head and beard were white like the Thaghamah. The Prophet [SAW] said: 'Change this, or dye it.'"  

أُتِيَ النَّبِيُّ ﷺ بِأَبِي قُحَافَةَ وَرَأْسُهُ وَلِحْيَتُهُ كَأَنَّهُ ثَغَامَةٌ فَقَالَ النَّبِيُّ ﷺ غَيِّرُوا أَوِ اخْضِبُوا