We know that which the earth takes of them [their dead bodies]...
We know that which the earth takes of them [their dead bodies], and with Us is a Book preserving all things in it. The Prophets’ warning rests on paying heed to Resurrection. By “far return,” disbelievers are saying that Resurrection does not stand to reason and common practice. Thus, disbelievers may not produce any argument against Resurrection but it merely sounds impossible to them.
Qur’anic exegets maintain that the interrogative particle opening Verse 3 reflects wonder and alludes to disbelievers’ denial of Resurrection saying that when they die and turn to dust, it would be next to impossible to be resurrected and return to life. Verse 4 is saying that disbelievers’ wonder at Resurrection on the Last Day is for their conception that when man dies, nothing will remain of his flesh, skin, and organs in the earth; thus it would be impossible to be rejuvenated.
The blessed Verse in question aims to remove their disbelief in Resurrection saying that they are not supposed to imagine that they turn into absolute non-existence when nothing remains of their bodies when they turn into dust.
In other words, their denial springs from their unfounded conception that when man dies, his flesh and bones turn into dust and become parts of the earth and particles of the same turn into gases and vapors as well and it would be impossible to collect them anew and find any intelligence as to their existence.
The response to such questions is that God Almighty whose Omnipotence encompasses all things, is All-Aware of such particles and shall collect them all when the need arises in such manner that the scattered particles of Iron may be collected from amongst a pile of dust using a magnet; it shall be far facile for God Almighty to collect the scattered particles of human beings.
In case disbelievers raise a question as to keeping records of human deeds for Resurrection, one may provide the response as per which all such records are being preserved in the ‘preserved tablet’ (lawh mahfud) and basically nothing will be lost in this world but deeds, despite alterations in their forms, remain. “Preserving Book” refers to a Book in which everything including human deeds are preserved in it.