Al-Kahf 18:104

Those whose efforts in the life of this world are wasted, while they think that they are doing well[54].”

[54] For they follow other than their Lord’s path, and justify their deviant actions until they finally believe that they are on the right path.

[They are] those whose effort is lost in worldly life, while they think that they are doing well in work."

104. "Those whose efforts have been wasted in this life while they thought that they were acquiring good by their deeds.[9]

[9] (V.18:104) For the acceptance of the righteous deeds it is stipulated that the following two basic conditions must be fulfilled:
a) The intentions while doing such deeds must be totally for Allâh’s sake only without any show-off or to gain praise or fame.
b) Such a deed must be performed in accordance with the Sunnah of Allâh’s Messenger Muhammad bin ‘Abdullâh صلى الله عليه وسلم , the last of the Prophets and the Messengers.
Narrated ‘Âishah رضي الله عنها : Allâh’s Messenger صلى الله عليه وسلم said, "If somebody innovates something which is not present in our religion (of Islâmic Monotheism), then that thing will be rejected." (Sahih Al-Bukhari, Vol.3, Hadith No.861).
In another Hadith narrated ‘Âishah رضي الله عنها: The Prophet صلى الله عليه وسلم said: "Whoever performs a (good) deed which we have not ordered (anyone) to do (or is not in accord with our religion of Islâmic Monotheism), then that deed will be rejected and will not be accepted." (Sahih Al-Bukhari, Vol.9, Chapter No.20 before Hadith No.449).

Those whose effort goeth astray in the life of the world, and yet they reckon that they do good work.