The Period of Revelation:
After the first revelation there came a pause extending over three years. The Prophet (Peace Be Upon Him) must have felt at first a shock, then a calm, an ardent desire, and after a period of waiting, a growing impatience. During the three years of waiting the Prophet (Peace Be Upon Him) had given himself up more and more to prayers and to spiritual practices. The revelations were then resumed and continued all through his life, since the Quran was not revealed all at once, but in fragments as occasions arose. The revelation of Quran was completed in the period of twenty-three years.