Reference: Fataawa tata’allaaq bil-Mawlid an-Nabawee – Page 49, Question 11
Al-Muntaqaa min Fataawa al-Fowzaan – Volume 1, Page 184
Question: We have a man with us at work who approves of the celebration of the birthday [of the Prophet ﷺ], and advocates and insists upon this. Should I abandon him for the Sake of Allaah or not?
What should I do? …and may Allaah reward you with good.
Response: Celebrating the Prophet’s birthday is an innovation, and whoever pursues this [path] is an innovator (mubtadi’) if he insists on doing so and does not accept the [sincere] advice, [rather, choosing to] continue in calling to [celebrating] the birthday and arousing interest in it. [In this case], then, it is obligatory to abandon him since he is an innovator, and it is not permissible to maintain companionship with an innovator.