Sunan an-Nasa'i, Volume 6, Book 48, Hadith 5083 (DarusSalam) ⓘ
It was narrated that Abu Dharr said: "The Messenger of Allah [SAW] said: 'The best things with which you can change gray hair are Henna and Katam.'"
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا عَبْثَرٌ، عَنِ الأَجْلَحِ، عَنْ عَبْدِ اللَّهِ بْنِ بُرَيْدَةَ، عَنْ أَبِي الأَسْوَدِ الدِّيلِيِّ، عَنْ أَبِي ذَرٍّ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِنَّ أَحْسَنَ مَا غَيَّرْتُمْ بِهِ الشَّيْبَ الْحِنَّاءُ وَالْكَتَمُ " . خَالَفَهُ الْجُرَيْرِيُّ وَكَهْمَسٌ .
also referenced under: Hadith 5080 (Reference) & Book 48, Hadith 41 (In-Book)