أَمَّنْ هَـٰذَا الَّذِي هُوَ جُندٌ لَّكُمْ يَنصُرُكُم مِّن دُونِ الرَّحْمَـٰنِ ۚ إِنِ الْكَافِرُونَ إِلَّا فِي غُرُورٍ (Now, who is there to become a force for you to help you, except the Rahman? The disbelievers are in nothing but delusion...67:20).
Then the next verse warns the disbelievers that the sustenance Allah grants them by sending down rain from the clouds and by growing plants/ vegetation in the earth is not their personal property. It is a gift and bounty from Allah. If He wills, He can withhold it. This is the import of the following verse: