The Quran

۞ وَإِن تَعجَب فَعَجَبٌ قَولُهُم أَإِذا كُنّا تُرابًا أَإِنّا لَفي خَلقٍ جَديدٍ ۗ أُولٰئِكَ الَّذينَ كَفَروا بِرَبِّهِم ۖ وَأُولٰئِكَ الأَغلالُ في أَعناقِهِم ۖ وَأُولٰئِكَ أَصحابُ النّارِ ۖ هُم فيها خالِدونَ

Muhammad Asad

BUT IF thou art amazed [at the marvels of God's creation], amazing, too, is their saying, "What! After we have become dust, shall we indeed be [restored to life] in a new act of creation?"¹ It is they who [thus show that they] are bent on denying their Sustainer;² and it is they who carry the shackles [of their own making] around their necks;³ and it is they who are destined for the fire, therein to abide.

I.e., while it is amazing that one can refuse to believe in God despite all the evidence, accessible to human observation, of the existence of a definite purpose in all life-phenomena, and thus of the existence of a conscious Creative Power, it is no less amazing to see people who, while vaguely believing in God, can yet refuse to believe in individual resurrection: for, if God has created the universe and the phenomenon of life as such, He obviously has the power to re-create life - and its requisite physical vehicle - in a new act of creation.
By denying the possibility of resurrection, they implicitly deny God's almightiness, and thus, in effect, His reality.
A metaphor of man's wilful self-abandonment to false values and evil ways, and of the resulting enslavement of the spirit (cf. Zamakhshari, Razi, Baydawl). See also surah 34, note 44.