Abu Hurairah (May Allah be pleased with him) said:
I heard the Messenger of Allah (ﷺ) as saying: "Jews and Christians do not dye their hair, so act differently from them."[Al-Bukhari and Muslim]. (DE)
App reference (DE): Book 18, Hadith 126 (DE)
Arabic/English book reference (DE): Book 18, Hadith 1636 (DE)