18:104
ٱلَّذِينَ ضَلَّ سَعْيُهُمْ فِى ٱلْحَيَوٰةِ ٱلدُّنْيَا وَهُمْ يَحْسَبُونَ أَنَّهُمْ يُحْسِنُونَ صُنْعًا
alladhīna ḍalla saʿyuhum fī l-ḥayati l-dun'yā wahum yaḥsabūna annahum yuḥ'sinūna ṣun'ʿan
whose efforts in this world are misguided, even when they think they are doing good work?
"Those whose efforts have been wasted in this life while they thought that they were acquiring good by their deeds.