Ibn 'Umar (RAA) narrated that the Messenger of Allah (ﷺ) said:
"He who imitates any people (in their actions) is considered to be one of them." Related by Abu Dawud and Ibn Hibban graded it as Sahih. (RU)
English reference (RU): Book 16, Hadith 1514 (RU)
Arabic reference (RU): Book 16, Hadith 1471 (RU)