274. hadíth
وَقَالَ أَمِيرُ اَلْمُؤْمِنِينَ عَلَيْهِ اَلسَّلاَمُ: «اَلْخِضَابُ هَدْيُ مُحَمَّدٍ صَلَّى اَللَّهُ عَلَيْهِ وَ آلِهِ وَ هُوَ مِنَ اَلسُّنَّةِ.
The Commander of the Faithful Imam Ali ibn Abi Talib (a.s) said: "Dyeing (the hair or beard) is the tradition of Muhammad (saws) and it is part of the Sunnah."