Watattakhithoona masaniAAa laAAallakum takhludoon (surah Shuara: 129)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(26:129) and build huge castles as if you were immortal; *91

Wa tattakhizoona masaani`a la`allakum takhludoon

*91) That is, ,"Though you have built other buildings also for dwelling purposes, in order to make them grand, beautiful and strong, you expend your wealth and mental and physical abilities in a manner as if you were going to live for ever, and there was no purpose of life except seeking of comfort and pleasure and nothing beyond this worldly life which might deserve your attention."
In this connection, one should bear in mind the fact that extravagance in architecture is not a solitary vice in a people. This happens as a result of a people's becoming affluent and then crazy for selfish gains and materialistic pursuits. When a people reach such a stage, their whole social system becomes corrupted and polluted. Prophet Hud's criticism of his people's extravagant and luxurious architecture was not simply aimed at the high castles and monuments, but he was actually criticising their corrupt civilization and social system, whose glaring symptoms could be seen everywhere in the land in the shape of castles and monuments.