Surat Al-Kahf (The Cave) - الكهف

قُلْ هَلْ نُنَبِّئُكُم بِٱلْأَخْسَرِينَ أَعْمَٰلًا ﴿١٠٣﴾ ٱلَّذِينَ ضَلَّ سَعْيُهُمْ فِى ٱلْحَيَوٰةِ ٱلدُّنْيَا وَهُمْ يَحْسَبُونَ أَنَّهُمْ يُحْسِنُونَ صُنْعًا﴿١٠٤﴾

Say: Shall We inform you of the greatest losers in (their) deeds? (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.