The following is extracted from “The Prophet Muhammad Musthafa the Elect (s.a.w.)” by Shaykh Osman Nuri Topbas.
Having completed the six-month preparation toward perfecting his spiritual development so that he was now ready to receive Divine Revelation, Prophet Muhammad (s.a.w.) was now forty years old. It was the seventeenth day of the holy month of Ramadhan.
The Noble Prophet (s.a.w.) was in the Cave of Hira as usual, when Jibril (a.s.) suddenly appeared and said, “Read!”
“I cannot read”, answered our Beloved Prophet (s.a.w.). Thereupon, the angel seized and constricted the Prophet (s.a.w.) so hard that he left him almost unable to breathe.
“Read!” Jibril (a.s.) then ordered once more.
But the Prophet Muhammad (s.a.w.) responded in the same manner: “I cannot read!”
The angel then seized him for the second time, compressing the Prophet (s.a.w.) until he had not strength to remain on his feet, repeating the command once again: “Read!”
“I cannot read!” answered the Blessed Prophet (s.a.w.), as if urging the angel to indicate what exactly it was he wanted him to read.
Jibril (a.s.) then forcefully squeezed the Prophet Muhammad (s.a.w.) for the third time and then released him, beginning shortly thereafter to reveal the very first Revelation.
In the Name of Allah, the Beneficent, the Merciful 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 ― He Who Taught (the use of) the Pen ― Taught man that which he knew not. (Qur’an Surah al-Alaq:1-5)
With this Divine Command, the Revelation of the Sacred Qur’an, the greatest benevolence of the Lord for the whole of mankind, began its long course of Revelation through the person of Muhammad the Messenger of Allah (s.a.w.)