وَمَا أَهْلَكْنَا مِن قَرْيَةٍ إِلَّا وَلَهَا كِتَابٌ مَّعْلُومٌ (4)
(15:4) We had prescribed a respite for every habitation that we destroyed before this. *2
*2) This is to refute the fallacious argument of the disblievers that Muhammad (Allah's peace be upon him) was not a true Prophet because they had received no prompt punishment for their disbelief. It is like this: "We have never seized a community at the first commital of kufr.
We prescribe a limit for every community to hear and understand the message and reform its ways. Then We tolerate its mischief and evil deeds up to that limit and allow it full freedom to do as it likes, and give it respite till the term expires. That is why We are tolerating their attitude of ridicule and denial. (For the full meaning of respite, please refer to E.N. 18 of Surah Ibrehim).