This is another indication of His gentleness and His mercy with His creatures. He is able to punish them because some of them disbelieve in Him and worship others besides Him, yet He is forbearing, He pardons, and He gives respite for an appointed time without hastening. This is as He says,

[وَلَوْ يُؤَاخِذُ اللَّهُ النَّاسَ بِمَا كَسَبُواْ مَا تَرَكَ عَلَى ظَهْرِهَا مِن دَآبَّةٍ وَلَـكِن يُؤَخِّرُهُمْ إِلَى أَجَلٍ مُّسَمًّى فَإِذَا جَآءَ أَجَلُهُمْ فَإِنَّ اللَّهَ كَانَ بِعِبَادِهِ بَصِيراً ]

(And if Allah were to punish men for that which they earned, He would not leave a moving creature on the surface of the earth; but He gives them respite to an appointed term: and when their term comes, then verily, Allah is Ever All-Seer of His servants.) [35:45] Here Allah says,

[أَءَمِنتُمْ مَّن فِى السَّمَآءِ أَن يَخْسِفَ بِكُمُ الاٌّرْضَ فَإِذَا هِىَ تَمُورُ ]

(Do you feel secure that He, Who is over the heaven, will not cause the earth to sink with you, and then it should quake) meaning, that it would move back and forth, and be disrupted.

[أَمْ أَمِنتُمْ مِّن فِى السَّمَآءِ أَن يُرْسِلَ عَلَيْكُمْ حَـصِباً]

(Or 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 لاَ تَجِدُواْ لَكُمْ وَكِيلاً ]

(Do 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 نَذِيرِ]

(Then 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,

[وَلَقَدْ كَذَّبَ الَّذِينَ مِن قَبْلِهِمْ]

(And indeed those before them rejected,) meaning, from the previous nations and the old generations that have passed. Then Allah says,

[فَكَيْفَ كَانَ نَكِيرِ]

(then how terrible was My reproach) meaning, `how was My rebuke of them and my punishment of them.' Meaning, it was great, severe and painful.