Fasting on the 12th of Rabiul Awwal
Q: Is it permissible to fast on the 12th Rabiul Awwal (the day of meeladun Nabi (Sallallahu alaihi wassalam)), in happiness of the birth of the prophet Muhammad (Sallallahu Alaihi Wassalam) without thinking of it as compulsory or is it a bidat and a sin?