Jabal Al Rahma or Arafat, is one of the rituals and key pillars of Hajj, which deems standing on Mount Arafa or Arafat and is located 20 kilometers east of Mecca. Standing at the day of Arafah on (the ninth of thu al-Hijjah (Arabic month) is the most important pillar of hajj as the Prophet, Peace be Upon Him, instructed.
Arafat is located outside the borders of Haram (Sanctuary site), with its total area reaching 10.4 km2. On the western boarders of Arafat is Irnah Valley. One of its main landmarks is Nimrah Mosque, where the Arafah prayer and sermon are held.
Arafah is believed as the day when the mercy of God descends, and Muslims are redeemed. It is one of the blessed days of the holy months and the day on which God completed Islam and His grace upon people. Fasting on the day of Arafah is preferred, it is believed that it atones for sins of the past and present year.
Source: Islamic Landmarks