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