Sahih Muslim
The Book Pertaining to the Excellent Qualities of the Holy Prophet (may Peace be upon them) and His Companions (Kitab Al-Fadail)
Book Number: 030 / Hadith Number: 5779
Ibn Sirin reported: Anas b. Malik was asked whether Allah's Messenger (may peace be upon him) dyed his hair. He said: He had not become old enough to have white hair. Ibn Idris said that he had a few white hair. Abu Bakr and Umar, however, dyed hair with hina' (henna).