importance of sincere intention

۞ أَجَعَلْتُمْ سِقَايَةَ ٱلْحَآجِّ وَعِمَارَةَ ٱلْمَسْجِدِ ٱلْحَرَامِ كَمَنْ ءَامَنَ بِٱللَّهِ وَٱلْيَوْمِ ٱلْـَٔاخِرِ وَجَـٰهَدَ فِى سَبِيلِ ٱللَّهِ ۚ لَا يَسْتَوُۥنَ عِندَ ٱللَّهِ ۗ وَٱللَّهُ لَا يَهْدِى ٱلْقَوْمَ ٱلظَّـٰلِمِينَ

Have you made the providing of water for the pilgrim and the maintenance of al-Masjid al-Ḥarām equal to [the deeds of] one who believes in Allāh and the Last Day and strives in the cause of Allāh? They are not equal in the sight of Allāh. And Allāh does not guide the wrongdoing people.

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."

ذَٰلِكَ بِأَنَّهُمُ ٱتَّبَعُوا۟ مَآ أَسْخَطَ ٱللَّهَ وَكَرِهُوا۟ رِضْوَٰنَهُۥ فَأَحْبَطَ أَعْمَـٰلَهُمْ

That is because they followed what angered Allāh and disliked [what earns] His pleasure, so He rendered worthless their deeds.

لِنَجْعَلَهَا لَكُمْ تَذْكِرَةً وَتَعِيَهَآ أُذُنٌ وَٰعِيَةٌ

That We might make it for you a reminder and [that] a conscious ear would be conscious of it.