There is no doubt that the first five verses of this surah represent the very beginning of the revelation of the Qur’an.
Although the exact date cannot be established with certainty, all authorities agree in that these five verses were revealed in the last third of the month of Ramadan, thirteen years before the hijrah (corresponding to July or August, 610, of the Christian era). Muhammad was then forty years old.
At that period of his life “solitude became dear unto him, and he used to withdraw into seclusion in a cave of Mount Hira [near Mecca] and there apply himself to ardent devotions” consisting of long vigils and prayers (Bukhari).
One night, the Angel of Revelation suddenly appeared to him and said, “Read!” Muhammad at first thought that he was expected to read actual script, which, being unlettered, he was unable to do; and so he answered, “I cannot read” – whereupon, in his own words, the angel “seized me and pressed me to himself until all strength went out of me; then he released me and said, ‘Read!’ I answered, ‘I cannot read. . . . ‘ Then he seized me again and pressed me to himself until all strength went out of me; then he released me and said, ‘Read!’ – to which I [again] answered, ‘I cannot read. . . .’ Then he seized me and pressed me to himself a third time; then he released me and said, ‘Read in the name of thy Sustainer, who has created – created man out of a germ-cell! Read – for thy Sustainer is the Most Bountiful One…’”: and so Muhammad understood, in sudden illumination, that he was called upon to “read”, that is, to receive and understand, God’s message to man