24:6
وَٱلَّذِينَ يَرْمُونَ أَزْوَٰجَهُمْ وَلَمْ يَكُن لَّهُمْ شُهَدَآءُ إِلَّآ أَنفُسُهُمْ فَشَهَـٰدَةُ أَحَدِهِمْ أَرْبَعُ شَهَـٰدَٰتٍۭ بِٱللَّهِ ۙ إِنَّهُۥ لَمِنَ ٱلصَّـٰدِقِينَ
wa-alladhīna yarmūna azwājahum walam yakun lahum shuhadāu illā anfusuhum fashahādatu aḥadihim arbaʿu shahādātin bil-lahi innahu lamina l-ṣādiqīna
As for those who accuse their own wives of adultery, but have no other witnesses, let each one four times call God to witness that he is telling the truth,
And for those who accuse their wives, but have no witnesses except themselves, let the testimony of one of them be four testimonies (i.e. testifies four times) by Allâh that he is one of those who speak the truth.