Surah Al-Mulk, ayah 25

67:25

وَيَقُولُونَ مَتَىٰ هَٰذَا ٱلۡوَعۡدُ إِن كُنتُمۡ صَٰدِقِينَ ٢٥

Wayaqūlūna matā hādhal-wa'du in kuntum sādiqīn

And they say, "When is this promise, if you should be truthful?"