Surah 39. Az-Zumar, Ayah 16

As in many other instances, the Qur'an alludes in this phrase to the allegorical nature as well as to the real purpose of all descriptions of the suffering which awaits the sinners in the hereafter; cf. {74:35-36}- "that [hell-fire] is indeed one of the great [forewarnings]: a warning to mortal man".

The consequences of Sin when Judgment comes are aptly figured by Layers upon Layers of Fire, which hem in the sinners above and below. It is also suggested that the Layers, though of Fire, have something dark in them-the scorching quality of Sin.

But Allah does not leave mankind without warning. Man has been granted a limited amount of free-will, and in order to help him in its right use, all the consequences of his action are clearly explained to him. To those who will listen to Reason are given arguments which can be apprehended by their own intelligence; to those who are swayed by affections and emotion, an appeal is made in the name of the love of Allah; to those who understand nothing but fear, the warning is conveyed by a portrayal of the dreadful consequences of wrong-doing.