Muhammad's first revelation

Muhammad's first revelation was an event described in Islamic tradition as taking place in 610 CE, during which the Islamic prophet Muhammad was visited by the angel Jibril (Gabriel), who revealed to him the beginnings of what would later become the Qur'an. The event took place in a cave called Hira, located on the mountain Jabal An-Nour near Mecca. The exact date and time of the revelation is not mentioned anywhere. As a result, the exact date is disputed. To stop the calendar months from rotating through the seasons, intercalation was employed. This involved the occasional insertion of an extra month (announced at the pilgrimage), ideally seven times in nineteen years. Intercalation was said to have been introduced in 412 CE, and it was borrowed from the Jews. The Jewish official controlling the practice was known as Nasīʾ. When the Arabs adopted the procedure they used this word nasīʾ to denote the whole system. It was operated similarly to the way the Jews operated it – the beginning of the year (Muharram) was tied to the spring season. According to Mubarak Puri, the exact date of this event was Monday, the 21st of Ramadan just before sunrise, i.e. August 10, 610 CE – when Muhammad was 40 lunar years, 6 months and 12 days of age, i.e. 39 solar years, 3 months and 22 days. Others establish the day by projecting the fixed (i.e. non-intercalated) calendar backwards, providing a date of the night of Sunday to Monday, 13 to 14 December 610. According to biographies of Muhammad, while on retreat in a mountain cave near Mecca (the cave of Hira), where Muhammad used to go and ponder upon the evil deeds of his community. Gabriel appears before him and commands him to "Read!". He responded, "But I cannot read!". Then the angel Gabriel embraced him tightly and then revealed to him the first lines of chapter 96 of the Qur'an, "Read: In the name of Allah Who created, (1) Created man from a clot. (2) Read: And Allah is the Most Generous, (3) Who taught by the pen, (4) Taught man that which he knew not.(5)" (Bukhari 4953).