Allatheena dalla saAAyuhum fee alhayati addunya wahum yahsaboona annahum yuhsinoona sunAAa (surah Kahf: 104)

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

(18:104) They are those, whose endeavours, in the worldly life, had all gone astray from the Right Way *76 but all along they were under the delusion that everything they were doing, was rightly directed:

Allazeena dalla sa`yuhum fil hayaatid dunyaa wa hum yahsaboona annahum yuhsinoona sun`aa

*76) This verse has two meanings. The one is the same that we have adopted in the translation. The other meaning is this: "...those who confined all their endeavours to the worldly life". That is, whatever they did, they did for this world without paying any regard to God and the Hereafter. As they considered the worldly life to be the real life, they made the success and prosperity in this world their sole aim and object. Even if they professed the existence of Allah, they never paid any heed to the two implications of this profession: to lead their lives in a way to please Allah and to come out successful on the Day they shall have to render an account of what they did in this world. This was because they considered themselves to be mere rational animals who were absolutely independent and free from every kind of responsibility and had nothing else to do but to enjoy the good things of the world like animals in a meadow.