A Meccan sura named after the heights of the barrier which will divide the righteous from the damned on the Day of Judgement (verse 46). The sura begins by addressing the Prophet, reassuring him about his revelations, and closes emphasizing the fact that he merely repeats what is revealed to him. It warns the disbelievers of their fate via numerous stories of disobedient communities of the past, in the hope that they may take heed and repent before it is too late. Both subjects also serve to give encouragement to the Prophet and the believers.
Source: The Qur’an (Oxford World’s Classics) by M. A. S. Abdel Haleem (Amazon Kindle Edition)