Surah Ar-Rum, ayah 6

وَعۡدَ ٱللَّهِۖ لَا يُخۡلِفُ ٱللَّهُ وَعۡدَهُۥ وَلَٰكِنَّ أَكۡثَرَ ٱلنَّاسِ لَا يَعۡلَمُونَ ٦

Wa'dallāhi lā yukhlifullāhu wa'dahū walākinna aktharan-nāsi lā ya'lamūn

[It is] the promise of Allāh. Allāh does not fail in His promise, but most of the people do not know.