Participating in the disbelievers parties and celebrations

Question 422: Is it permissible for Muslims to accept the Christians’ invitations to their parties and occasions and vice versa?

Answer: It is not permissible to share in the festivals and religious celebrations held by non-Muslims, for Allaah, the Exalted, described the Servants of the Most Beneficent (Allaah) as And those who do not bear witness to falsehood The word “falsehood” is interpreted as “the disbelievers’ festivals,” and “bear witness” [in Arabic “yash-hadun;” which could mean “bearing witness” or “attending, partaking, etc.”] is interpreted as”attending and participating in them.”... read more here.