The Holy Prophet (S) use to spend a lot of his time in the cave Hira, which is in a mountain overlooking the Holy Ka'ba, some three miles north of Makka.Here he would think about Allah and wonder at His creations. He would also think about the actions of the people of Makka and their bad habits made him sad. It was his habit to sometimes spend a few days continuously in the cave in prayers, and his wife Bibi Khadija (A) would bring him some food and water.

One night when he was in the cave of Hira, he heard a voice calling his name and suddenly there was a dazzling light in the cave. The Holy Prophet (S) sat at his place calmly and saw that a man was approaching him. The person was none other than Angel Jibraeel (A) in human form.

Jibraeel (A) came very close to the Holy Prophet (S) and asked him to recite the words which were the first revelation from Allah. These later became the first five verses of Surah al-Alaq. They read:

"In the Name of Allah the Beneficent, the Most Merciful. Read! In the Name of your Lord Who created (everything in the Universe). He created man from a clot. Read! And your Lord is the Most Honourable. (He) Who taught (to write) with the pen. (He) taught man what he knew not."
Alaq, 96:1-5

When the Holy Prophet (S) had finished reciting, the angel announced, "O Muhammad! There is no doubt that you are the Apostle of Allah and I am his angel Jibraeel." After saying this, the angel disappeared.

This event told the Holy Prophet (S) that it was now time to start his mission. At this time he was 40 years old. The date was 27th of Rajab, 610 A.D. Also at this time, Allah blessed the Holy Prophet (S) with such a memory that, whatever he heard only once from Jibraeel (A), remained in his heart forever.

The Holy Prophet (S) then left the cave to return home, where he would begin his mission to preach the Unity of Allah and to invite all mankind to the path of worshipping only One God.