Overall meaning : It is Allah who has endowed you, mankind, with hearing, sight and the hearts with which you reason, yet little thanks do you give.
It is He who has created you and dispersed you all over earth, and before Him alone will you all be gathered on the Day of Resurrection for judgement. It is He who gives life and causes death and controls the alternation of night and day. Will you not, then, use your reason to understand this?!
These unbelievers, however, do not reflect on these signs and proofs. Rather, they deny the resurrection and only parrot what their forefathers—who likewise denied it—said before them.

They said, ‘When we are dead and turned to dust and bones in our graves, will we really be raised to life?! This will never happen. We have already been threatened with this, as were our forefathers before as, but we have not seen such threat being carried out. The resurrection is nothing by lies of the ancients which they had themselves fabricated and recorded in their books!