The surah can be divided into the following eight sections.
Section I (1-5)
A close scrutiny of the universe reveals that its sovereign is a Blessed and Powerful Being. He has created this world with a purpose: it has been created as a trial and test for man as to who adopts the right path and who the wrong one. A necessary outcome of this trial is that a Day should come wherein the righteous be rewarded and the rebellious be punished. If this universe is carefully observed, not even a minor flaw can be pointed out in its great expanse. Repeated observations will only second this inference. The nearest of the seven skies has been adorned with stars by the Almighty; they serve the dual purpose of guiding people in their journeys and pelting Satan and his army if they try to overhear something.
Section II (6-11)
The power and sustenance of the Almighty so evident in this universe bears evidence that those who deny the Day of Reward and Punishment will have to face the torment of hell. It will roar and shriek like a hungry lion when it sees them. Whenever a group of these rebellious people will be flung in hell, its gate-keepers will ask them whether a warner had ever warned them of this punishment. They would admit that a warner did come to them but they rejected him and had replied that the Almighty had revealed nothing and that whoever believe that the Almighty has revealed anything have, in fact, deviated from the right path. They would also confess that they had never tried to listen to and understand what had been said to them, otherwise they would not have met this fate.
Section III (12-14)
People who remain fearful of their Lord in this world shall be rewarded. All their virtuous deeds are in the knowledge of Allah and He shall duly honour them. He is the Creator of all and nothing is hidden from Him.
Section IV (15-18)
This earth has been created by the Almighty as very obedient and submissive to man. It is a source of reminder for man of a great reality: he should fully benefit from all its pleasures and facilities but should always keep in mind that these privileges entail a day of accountability before the Almighty; not even for a moment should a person become unmindful of his Lord's grasp and should always remember that whenever the Almighty intends, He can destroy him by sending on him a natural calamity. History also bears example to this.
Section V (19-21)
Whatever is suspended in the unfathomable skies is held by the Almighty. He is watching everything. If someone is deprived of His assistance and support, no one will be able to help him. If He deprives someone of sustenance, no one will be able to sustain him.
Section VI (22-23)
Those who lead their lives while remaining a slave to their desires will never reach the real goal. Only they will reach this goal who remain on the right path. The Almighty has endowed people with the faculties of sight, hearing and reasoning so that people can remain on the right path by using them. But alas! very few people understand the worth of such favours.
Section VII (24-27)
The Almighty has spread man in this earth and He Himself shall definitely gather him one day. The Prophet (sws) is told to inform the disbelievers that only Allah knows when the Day of Judgement will come and that he himelf has no knowledge of its time of arrival; he has only been sent to warn them about it and not to inform them about its time of arrival. However, when the Day does arrive, the faces of the disbelievers will turn black with gloom.
Section VIII (28-30)
If these disbelievers are awaiting the change of fortunes for the Prophet (sws) and his Companions, and suppose that this change does happen, then why should they themselves rest assured? They shall certainly meet the dreadful fate they have been informed of.
(Translated from Islahi's "Tadabbur-i-Qur'an") -- Shehzad Saleem