The surah can be divided into the following three sections.
Section I (1-5)
The Prophet (sws) has been checked in a particular matter in which though his motivating force was fairly admirable yet since he was to become an example for the whole Ummah, any virtuous deed which crosses the limits set by Allah is not permissible. The Prophet (sws) might be doing something to console and please his wives and he might be showing sympathy to their perfectly human weaknesses, yet owing to his position as a Prophet (sws) he must remain within the bounds set by Allah even in the smallest of affairs.
Similarly, the pious wives have been checked in a matter in which something said by the Prophet (sws) to a particular wife was disclosed by her to another wife, though in an atmosphere of mutual trust. However, since they too are to become an example for all women of the Ummah, even a small instance which crosses the limits set by Allah cannot be tolerated from them. The higher the position and status of a person, the higher the extent of his accountability.
Section II (6-8)
After checking the Prophet (sws) and his wives, the general Muslims are urged to check and restrain their near ones. Everyone should remember that the angels who guard hell are strict and stern. They shall show no lenience to anyone. On the Day of Judgement, no excuse of a person will be acceptable, for he shall be facing only what he deserves and no one shall be punished for more than what he has done. Only those will triumph on that Day whose pure repentance makes them eligible for the Almighty's blessings. It will be a Day of success for the Prophet (sws) and his Companions. The Almighty shall perfect their light which shall lead them to paradise. Everyone else shall be doomed forever.
Section III (9-12)
The Prophet (sws) has been emphatically directed to tell the disbelievers and the hypocrites sternly to change their attitude lest they should end up in the raging fire of hell which, of course, is the worst abode. At the end, examples of the wives of the Prophet Noah (sws) and the Prophet Lot (sws) are cited to the disbelievers and those of the wife of the pharoah and Hadhrat Maryam (rta) to the Muslims, the object being to prove that only a person's deeds will be of any benefit to him in the Hereafter. If a woman has not done righteous deeds, she cannot benefit in the Hereafter even if she is the wife of a Prophet. Similarly, if a woman has lived a pious life, she shall be rewarded in the Hereafter even though she is the wife of a person as rebellious as the Pharoah.
(Translated from "Tadabbur-i-Quran") ---Shehzad Saleem