Hadith 4209
حَدَّثَنَا مُحَمَّدُ بْنُ عُبَيْدٍ، حَدَّثَنَا حَمَّادٌ، عَنْ ثَابِتٍ، عَنْ أَنَسٍ، أَنَّهُ سُئِلَ عَنْ خِضَابِ النَّبِيِّ، صلى الله عليه وسلم فَذَكَرَ أَنَّهُ لَمْ يَخْضِبْ وَلَكِنْ قَدْ خَضَبَ أَبُو بَكْرٍ وَعُمَرُ رَضِيَ اللَّهُ عَنْهُمَا .
Thabit said that Anas was asked about the hair-dye of the Prophet (ﷺ). He replied:He did not dye his hair, but Abu Bakr and 'Umar dyed their hair
Sahih (Al-Albani)
Sunan Abi Dawud 4209 · Book 35, Hadith 51