Al-Kahf 18:98

Qala hatha rahmatun minrabbee fa-itha jaa waAAdu rabbee jaAAalahu dakkaawakana waAAdu rabbee haqqa

[Dhul-Qarnayn] said, "This is a mercy from my Lord; but when the promise of my Lord comes [i.e., approaches], He will make it level, and ever is the promise of my Lord true."

He said, “This is a mercy from my Lord. Then, when the promise of my Lord will come, He will make it leveled to the ground. The promise of my Lord is true.”