Mount Arafah is a granite hill about 20 km (12 mi) southeast of Mecca in the plain of Arafah. Mount Arafah reaches about 70 m (230 ft) in height and is known as the "Mountain of Mercy" (Jabal ar-Rahmah). According to Islamic tradition, the hill is the place where the Islamic prophet Muhammad stood and delivered the Farewell Sermon to the Muslims who had accompanied him for the Hajjtowards the end of his life.
On 9 Dhu al-Hijjah before noon, pilgrims arrive at Arafah, a barren plain some 20 kilometers east of Mecca, where they stand in contemplative vigil: they offer supplications, repent and atone for their past sins, seek mercy of God, and listen to Islamic scholarsgiving sermons from near Mount Arafah. Lasting from noon through sunset, this is known as 'standing before God' (wuquf), one of the most significant rites of Hajj. At Namrah Mosque, pilgrims offer Zuhr and Asr prayers together at noon time. A pilgrim's Hajj is considered invalid if they do not spend the afternoon on Arafah.
As Husayn ibn Ali recited the prayer during the Hajj at Mount Arafah on 9 Dhu al-Hijjah, Muslims during the Hajj recite the Arafah prayerfrom Zuhr prayer to sunset. This day is called prayer day, specially for people who stand on Mount Arafah. On day of Arafah, Shia Muslims go to holy places such as mosques and graves of Shi'a Imams to recite Arafah prayer.
Occurrence in hadith
'There is no day on which Allah frees more people from the Fire than the Day of Arafah. He comes close and expresses His fulfillment to the angels, saying, 'What do these people want?'