Mehrab-e-Tahajjud

This raised platform, behind the Roza Mubarak and in line with Bab-e-Jibraeel, is the approximate place where the Prophet (s.a.w.) used to spread his prayer mat and perform the Tahajjud salah from time to time.

- Isa bin Abdullah (r.a.) said, “When visitors used to depart at night, the Prophet (s.a.w.) used to spread a mat behind Ali’s (r.a.) hut and used to offer voluntary salat there. One day one person saw him offering voluntary salat at this spot during the month of Ramadhan. This person also started offering voluntary salat at this spot. Another person happened to pass this way and he started his salat also. A third person followed these two persons. By and by a large number of people gathered there. When the Prophet (s.a.w.) saw many people he wrapped up his praying mat and went away. When these people met Prophet (s.a.w.) in the morning, they said, “We were only trying to follow you in offering voluntary salat at night.“ The Prophet (s.a.w.) said, “I was concerned about you very much. My concern was that Allah (swt) may make the offering of night salat during Ramadhan obligatory for you and you may fail to keep up with it.”

References:
History of Madinah Munawwarah – Dr. Muhammad Ilyas Abdul Ghani