يَا نِسَاءَ النَّبِيِّ مَن يَأْتِ مِنكُنَّ بِفَاحِشَةٍ مُّبَيِّنَةٍ يُضَاعَفْ لَهَا الْعَذَابُ ضِعْفَيْنِ ۚ وَكَانَ ذَٰلِكَ عَلَى اللَّهِ يَسِيرًا (30)
(33:30) Wives of the Prophet, if any of you commit flagrant indecency, her chastisement shall be doubled. *43 That is easy for Allah. *44
*43) This does not mean that three was, God forbid, any chance of the Holy Prophet's wives committing an indecency, but this was meant to make them realize that they were the mothers of the Muslims; therefore, their responsibilities were accordingly very high, and so their moral conduct should be the purest. This is ,just like Allah's addressing the Holy Prophet to the effect: "If you committed shirk, all your works would be rendered vain." (Az-Zumar: 65). This also does not mean that there was, God forbid, any chance of the Holy Prophet's committing shirk, but this is meant to make the Holy Prophet realize, and through him the common Muslims, that shirk, is a most heinous crime which must be guarded against most judiciously.
*44) That is, "You should not be under the delusion that your being the Prophet's wives will protect you from Allah's punishment, or that it will be difficult for Allah to call you to account on account of your high rank and position in the world."