It was narrated that Ibn Umar (radiyallahu anhum ajmain) said: Rasulullah (sallallahu alayhi wa sallam) said:
مَنْ تَشَبَّهَ بِقَوْمٍ فَهُوَ مِنْهُمْ
Whoever imitates a people is from them. (Abu Dawud, #4031)
Shaykh'ul Islam Ibn Taymiyyah after mentioning the Isnaad (chain) of this Hadith being Jayyid (good) and also Imam Ahmad and others quoted this Hadith as evidence, said the following:
This Hadith at the very least implies that it is Haraam (unlawful) to imitate them (i.e., the Kuffar) even though the Dhahir (apparent) of this Hadith as it was in the Ayah: And if any amongst you takes them (i.e., Jews and the Christians) as Awliya (friends), then surely he is one of them. (al-Ma’idah 5/51) necessitates imitation of them to be Kafir.
This is similar to the view of Abdullah ibn Amr (radiyallahu anhum ajmain): “Whoever builds (a building and settles) in the land of the Mushrikin and celebrates their (festival of) Nawroz (new year) and (festivals of theirs) Mahrajaan and imitates them until he dies will be gathered with them on the Day of Resurrection.”
This may be interpreted as referring to absolute imitation which implies Kufr and necessitates parts of it to be Haraam. Sometimes it may be interpreted as meaning that he is one of them to the extent that he imitates them. If it (i.e., imitating concerning) is in ideas of Kufr, Masiyah (sin) or the Shiar (signs and partaking in a ritual) then its Hukm (ruling) will be accordingly. (Iqtida’us Siraat’il Mustaqim, 1/271)
