Qur'an 18:98

قَالَ هَـٰذَا رَحْمَةٌ مِّن رَّبِّى ۖ فَإِذَا جَآءَ وَعْدُ رَبِّى جَعَلَهُۥ دَكَّآءَ ۖ وَكَانَ وَعْدُ رَبِّى حَقًّا

“[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."”

Al-Kahf 18:98 · Saheeh International