The Prophet has said: "I had fallen asleep in the grotto of Hira, when the angel Jibra'il appeared to me, and unfolding before my eyes a long strip of silken stuff embroidered with written letters: 'Read!' said he.—'I am not one of those who read,' I replied. He caught hold of me at once, tightening the silken folds round my limbs, mouth and nostrils with such violence that I could not breathe. I thought the hour of my death had arrived.
"Letting me go, he repeated: 'Read!'—'I am not one of those who read,' I answered as before. Again he clutched me and I felt my last breath about to escape from my breast. Finally he loosened his hold and repeated for the third time: 'Read!'—'What am I to read?' I asked, in my affright lest he tighten the silk around me anew and this time I felt certain that my lungs would not have held out.
"It was then that he said to me: 'Read! in the name of thy Lord who created * Created man from clots of blood * Read! For thy Lord is the most beneficent * Who hath taught the use of the pen * Hath taught Man that which he knew not.' (The Qur'an, xcvi, 1-5).
"I recited these words after him. He vanished. Starting out of my sleep, I had the impression that the whole of a Book had just been engraved on my heart.
"I went out of the cave to collect my thoughts, when halfway down the mountain, I heard a voice that came from Heaven, crying out to me: 'O Mohammad, thou art the Prophet of Allah and I am Jibra'il!' I raised my glance to the sky. It was filled by Jibra'il's presence. Despite all I could do to turn my eyes, wellnigh blinded, in the direction of other parts of the horizon, the angel's dazzling apparition was always before me. And I stood rooted to the spot, unable to go backwards Or forwards. I was petrified.
"For the second time, Jibra'il said to me: 'O Mohammad, thou art the Prophet of Allah and I am Jibra'il!' He then disappeared like a vision in a dream. It was then that in great haste, my heart beating in the most terrible anguish, I ran towards my dwelling...."
The Encampment.