The surah can be divided into the following six sections.
Section I (1-4)
The surah begins with the assertion that this world has not been created without a purpose. The effort undertaken by the Almighty in the creation of man to sustain and nourish him bears witness to the fact that the Day of Reckoning is certain to come. Allah, the Lord and Creator of this world is well aware of every person's deeds. He shall treat each person accordingly.
Section II (5-7)
By citing historical evidence, it is shown that nations, who denied their Prophets and vainly rejected their sound arguments on the pretext that accepting a human being as a Prophet (sws) is an insult to them, were all destroyed by Allah. They met a dreadful fate in this world and in the Hereafter they shall encounter a grave punishment.
Section III (8-10)
The disbelievers are invited to profess faith in Allah, His Prophet (sws) and the Quran. They are urged to prepare for the Day which will decide the victor and the vanquished. On that Day, the righteous shall receive the eternal reward of paradise, while the disbelievers shall have to reckon with the eternal torment of Hell.
Section IV (11-13)
It is asserted that troubles and hardships which a person has to face in his life come from Allah. It is not befitting for the believers to get apprehensive about them and turn away from the obedience of Allah and His Prophet (sws). It is the requirement of their faith that they should have trust in the Almighty: He will certainly help them. If they ignore Allah and the Prophet (sws) by being overawed by their hardships, they shall bear its dire consequences. The responsibility of the Prophet (sws) was only to communicate the truth; it is now their responsibility to abide by it.
Section V (14-15)
Muslims are warned that at times one's family becomes a great test for his faith. Their love sometimes negatively affects his determination to fulfil his religious obligations. A person should always remain careful in this matter. However, he should adopt the attitude of `to forgoe and forget' in their regard.
Section VI (16-18)
People are invited to obey Allah and His Prophet (sws) as much as they can and urged to generously spend in the way of Allah. Glad tidings are given of eternal success to those who protect themselves from the malady of miserliness. Allah will greatly honour those who will lend Him their wealth. It shall be returend to them multiplied many times; He would also forgive them. He has knowledge of both the seen and the unseen: He is fully aware of all virtuous deeds however secretly they might have been done.
(Translated from Islahi's "Tadabbur-i-Quran") ----Shehzad Saleem