Al-Kahf · Ayah 104
ٱلَّذِينَ ضَلَّ سَعْيُهُمْ فِى ٱلْحَيَوٰةِ ٱلدُّنْيَا وَهُمْ يَحْسَبُونَ أَنَّهُمْ يُحْسِنُونَ صُنْعًا
[They are] those whose effort is lost in worldly life, while they think that they are doing well in work."
Quran 18:104 (Al-Kahf) · Saheeh International, Noor International Center (QuranEnc v1.1.2)