Surah An-Nahl, Verse 91

وَأَوۡفُواْ بِعَهۡدِ ٱللَّهِ إِذَا عَٰهَدتُّمۡ وَلَا تَنقُضُواْ ٱلۡأَيۡمَٰنَ بَعۡدَ تَوۡكِيدِهَا وَقَدۡ جَعَلۡتُمُ ٱللَّهَ عَلَيۡكُمۡ كَفِيلًاۚ إِنَّ ٱللَّهَ يَعۡلَمُ مَا تَفۡعَلُونَ٩١

wa-awfū biʿahdi l-lahi idhā ʿāhadttum walā tanquḍū l-aymāna baʿda tawkīdihā waqad jaʿaltumu l-laha ʿalaykum kafīlan inna l-laha yaʿlamu mā tafʿalūna

And fulfill the covenant of Allāh when you have taken it, [O believers], and do not break oaths after their confirmation while you have made Allāh, over you, a security [i.e., witness]. Indeed, Allāh knows what you do.