Al-Kahf - 18:104

الَّذِينَ ضَلَّ سَعْيُهُمْ فِي الْحَيَاةِ الدُّنْيَا وَهُمْ يَحْسَبُونَ أَنَّهُمْ يُحْسِنُونَ صُنْعًا
[18:104]
(These are) they whose labor is lost in this world's life and they think that they are well versed in skill of the work of hands.
"Those whose efforts have been wasted in this life, while they thought that they were acquiring good by their works?"
Those whose effort goeth astray in the life of the world, and yet they reckon that they do good work.