Is it permissible to congratulate or give greetings to non-Muslims on their holidays? Furthermore, is it permissible to participate in their celebrations?
It is permissible to congratulate or greet people of the book (i.e., Christians and Jews) or other religions on the occasions they celebrate, such as New Year’s Day, birth of Jesus (p) on Christmas, and Easter. And there is no problem participating in their celebrations per se, unless it entails engaging in impermissible practices or the promotion of false beliefs.