أَفَلَا يَعْلَمُ إِذَا بُعْثِرَ مَا فِى ٱلْقُبُورِ

  So does he not know? When those in the graves are raised,

Tafsir al-Baghawi                                                     تفسیر البغوی                            

{أَفَلَا يَعْلَمُ} أَيْ: أَفَلَا يَعْلَمُ هَذَا الْإِنْسَانُ، {إِذَا بُعْثِرَ} أَيْ: أُثِيرَ وَأُخْرِجَ، {مَا فِي الْقُبُورِ} [مِنَ الْمَوْتَى]

So does he i.e. the humans, not know?  When those, corpses, from the graves will be raised i.e. emerged and come out.

Tafsir al-Baghawi (Ma’aalim al-Tanzeel) of Muhiyy al-Sunnah Imam Abu Muhammad Al-Husain ibn Mas’ood al-Baghwi al-Shafe’I t D. 510 A.H.