Tafsir of Al-Kahf 18:59

وتلك القرى أهلكناهم لما ظلموا

And these towns, We destroyed them when they did wrong. This refers to earlier nations in times past; `We destroyed them because of their stubborn disbelief.'

وجعلنا لمهلكهم موعدا

And We appointed a fixed time for their destruction. `We appointed for them a set time limit, not to be increased or decreased. The same applies to you, O idolators, so beware or what happened to them will happen to you too, for you have rejected the noblest Messenger and greatest Prophet, and you are not dearer to Us than them, so fear My punishment and wrath.'