Al-Kahf • EN-TAFSIR-IBN-ABBAS
﴿ ٱلَّذِينَ ضَلَّ سَعْيُهُمْ فِى ٱلْحَيَوٰةِ ٱلدُّنْيَا وَهُمْ يَحْسَبُونَ أَنَّهُمْ يُحْسِنُونَ صُنْعًا ﴾
“"[It is] they whose labour has gone astray in [the pursuit of no more than] this world's life, and who none the less think that they are doing good works:”
(Those whose effort goeth astray) those whose works are thwarted (in the life of the world) these are the Kharijites; and it is also said that this refers to anchorites, (and yet they reckon that they do good work) and yet think that they are doing righteous works.