Al-Mash`ar Al-Haram is the Valley between Muzdalifah and Mina, where pilgrims should make a Du`a’ after they have slept in Muzdalifah while they are going to Makkah to throw Jamrat Al-`Aqabah on the morning of the 10th of Dhul-Hijjah.
The rationale behind this is that the Arabs during the Pre-Islamic period used to gather together in that arena to carry out literary competitions and discussions regarding lineage and dignity and other material values of this present life. However, with the advent of Islam, Allah the Almighty prescribed for Muslims standing in the same place but to do something better. That’s to stand in that very place to remember and glorify Allah the Almighty, the only and One Creator. In this way, they show their dignity and elevated status over the polytheists and to send them a clear message indicating that there is neither honor, nor dignity, nor glory save in Islam; in fact, this is a great piece of wisdom.