مَّا كَانَ عَلَى النَّبِيِّ مِنْ حَرَجٍ فِيمَا فَرَضَ اللَّهُ لَهُ ۖ سُنَّةَ اللَّهِ فِي الَّذِينَ خَلَوْا مِن قَبْلُ ۚ وَكَانَ أَمْرُ اللَّهِ قَدَرًا مَّقْدُورًا (38)
(33:38) There could be no hindrance to the Prophet regarding what Allah ordained for him. *74 Such has been Allah's Way (with the Prophets) who went before. Allah's command is a decree firmly determined. *75
*74) These words show that for the other Muslims such a marriage is just permissible but for the Holy Prophet it was a duty which Allah had imposed on him.
*75) That is, "For the Prophets it has always been a law that whatever Command they receive from Allah, they have to act on it as a duty which they cannot in any case avoid. When Allah enjoins something on His Prophet, he has to accomplish it even if the whole world is deadly opposed to it."