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]. (ID)
App reference (ID): Book 18, Hadith 126 (ID)
Arabic/English book reference (ID): Book 18, Hadith 1636 (ID)