This is Mount Hira (Jabal Hira), which lies about two miles from the Ka’bah. Near the top is a small cave, a little less than 4 meters in length and a little more than one and a half meters in width. It was here that the Prophet Muhammad (peace and blessings of Allah be on him) received the first revelations of the Holy Quran during the month of Ramadhan in 610 CE. The mountain is also known as Jabal Noor (the Mountain of Light).
During Tahajjud time one night, when he was alone in the cave, there came to him an angel in the form of a man. The angel said to him, “Recite!”. “I cannot read”, the Prophet (peace and blessings of Allah be on him) replied. The angel took hold of him a second time and pressed him until he could not endure it any longer. After letting him go, the angel again said, “Recite!”. Again the Prophet (peace and blessings of Allah be on him) replied “I cannot read”. The angel further embraced him again until he had reached the limit of endurance and said “Recite!” for the third time the Prophet (peace and blessings of Allah be on him) said “I cannot read”. The angel released him and said: “Read in the name of your Lord, the Creator. He Who created man from a clot. Read! And your Lord is the Most Bounteous. Who taught by the Pen, taught man what he knew not.” [96:1-5]