وَلَقَدْ كَذَّبَ الَّذِينَ مِن قَبْلِهِمْAnd indeed those before them rejected,meaning, from the previous nations and the old generations that have passed.Then Allah says,فَكَيْفَ كَانَ نَكِيرِthen how terrible was My reproach? meaning, `how was My rebuke of them and my punishment of them.' Meaning, it was great, severe and painful. The flight of Birds is by the Power of Allah and it is a Proof that He sees everything small and large Allah says