THERE ARE considerable differences of opinion regarding the period in which this surah was revealed.According to one statement attributed to Ibn 'Abbas, it is a Meccan surah (Suyuti), while according to other authorities, mentioned by Tabarani, Ibn 'Abbas is reported to have described it as belonging to the Medina period (ibid.). Suyuti himself inclines to the view that it is a Meccan surah but contains a few verses revealed at Medina; and so do Baghawi and Razi. Zamakhshari, on the other hand, confines himself to the statement that the time of its revelation is uncertain. Like so many other surahs, this one, too, takes it's title from the incidental mention of a word which caught the imagination of the earliest generation of Muslims: in this case, the word "thunder" occurring in verse 13, which relates to the evidence of God's creative powers forthcoming from the observable manifestations of nature. The main theme of this surah is God's revelation, through His prophets, of certain fundamental moral truths which man may not neglect without suffering the natural consequences of such a neglect (see the last paragraph of verse 31 and note 57) - just as a realization of those moral truths by those "who are endowed with insight... [and] are true to their bond with God" (verses 19-20) invariably causes them to "find inner happiness and the most beauteous of all goals" (verse 29): for, "God does not change men's condition unless they change their inner selves" (verse 11).