Surah An-Noor, Verse 6
وَٱلَّذِينَ يَرْمُونَ أَزْوَٰجَهُمْ وَلَمْ يَكُن لَّهُمْ شُهَدَآءُ إِلَّآ أَنفُسُهُمْ فَشَهَٰدَةُ أَحَدِهِمْ أَرْبَعُ شَهَٰدَٰتٍۭ بِٱللَّهِ ۙ إِنَّهُۥ لَمِنَ ٱلصَّٰدِقِينَ
Translation — Sahih International
And those who accuse their wives [of adultery] and have no witnesses except themselves - then the witness of one of them [shall be] four testimonies [swearing] by Allah that indeed, he is of the truthful.
Source
Kur'an-ı Kerim, Nûr Suresi 24:6
https://kuran.diyanet.gov.tr/mushaf/kuran-meal-2/24-suresi-6-ayet