Quran 24, An-Nur (Light) ⓘ

24:6As for those who accuse their wives but have no witnesses except themselves; let the testimony of one of them be four testimonies, (swearing) by Allah that he is of those who speak the truth;

وَالَّذِينَ يَرْمُونَ أَزْوَاجَهُمْ وَلَمْ يَكُنْ لَهُمْ شُهَدَاءُ إِلَّا أَنْفُسُهُمْ فَشَهَادَةُ أَحَدِهِمْ أَرْبَعُ شَهَادَاتٍ بِاللَّهِ إِنَّهُ لَمِنَ الصَّادِقِينَ