أَمْ أَمِنتُم مَّن فِي السَّمَاء أَن يُرْسِلَ عَلَيْكُمْ حَاصِبًاOr do you feel secure that He, Who is over the heaven, will not send against you a Hasib?meaning, a wind containing gravel that will strike you, as Allah says in another Ayah,أَفَأَمِنتُمْ أَن يَخْسِفَ بِكُمْ جَانِبَ الْبَرِّ أَوْ يُرْسِلَ عَلَيْكُمْ حَاصِبًا ثُمَّ لَا تَجِدُواْ لَكُمْ وَكِيلًDo you then feel secure that He will not cause a side of the land to swallow you up, or that He will not send against you a violent sandstorm Then, you shall find no trustee. (17:68)And similarly, here Allah threatens them with His statement,فَسَتَعْلَمُونَ كَيْفَ نَذِيرِThen you shall know how has been My warning.meaning, `how is My admonition and what will happen to those who disregard and reject it.'Then Allah says