The night of 27 Rajab is known as Shab e Meraj. Muslims prefer to do ibadah at night and fast on next day. Up till, several Islamic scholars have written about 27 Rajab Ke Roze Ki Fazilat in their books.
Shab e Meraj, Lailat al Miraj, or Isra Wal Miraj is the sacred night. Our beloved Prophet Muhammad (Peace Be Upon Him) crossed through the seven heavens and Sidratul Muntaha. He (Peace Be Upon Him) met with Allah and the five times prayers were also become obligatory on that auspicious night. Each year, Shab e Meraj is observed with the religious enthusiasm. However, a lot of people also fast next day as different narrations are present about 27 Rajab ke roze ki fazilat. According to one narration, the reward of fasting on 27 Rajab is equal to the fasting for 60 months. It is also believed that it protects a person from the punishment of hell and grave’s trial.