Question: Is it permissible for a Muslim to join the Christians in their celebrations, such as Christmas that is held at the end of December? Some people who claim knowledge sit with Christians in their feast gatherings and say that it is permissible. Is their opinion true or false? Is there any legal evidence for the permissibility of doing so?
Answer: It is not permissible to join the Christians in their celebrations, even if those who claim knowledge join them, because this increases their numbers and is a kind of support to them in sin and transgression. Allaah (Exalted be He) says (what means): Help you one another in Al-Birr and At-Taqwaa (virtue, righteousness and piety); but do not help one another in sin and transgression.… read more here.