According to Islam Muhammad's first revelation was the event in which Muhammad was visited by the Arch-angel Gabriel, in the year 610 CE, who revealed to him a verse from the Quran.
According to biographies of Muhammad the Arch- angel Gabriel appears to him and commands him to recite the first lines of Chapter 96 of the Quran, Muhammad replied to the Arch-angel that he was unable to recite it. So Gabriel, the Arch-angel, caught hold of him and embraced him heavily.
This happened two more times after which the angel commanded Muhammad to recite the following verses:
Proclaim! (or read!) in the name of thy Lord and Cherisher, Who created-
Created man, out of a (mere) clot of congealed blood:
Proclaim! And thy Lord is Most Bountiful,-
Who taught (the use of) the pen,-
Taught man that which he knew not.
—Quran, sura 96 (Al-Alaq), ayat 1-5[10]