(18) باب فِي الْخِضَابِ
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.
Reference: Sunan Abi Dawud 4209
In-book reference: Book 35, Hadith 51
English translation: Book 34, Hadith 4197