24-Surah An-Noor ( The Light ) 23
Indeed, those who [falsely] accuse chaste, unaware and believing women are cursed in this world and the Hereafter; and they will have a great punishment
إِنَّ الَّذِينَ يَرْمُونَ الْمُحْصَنَاتِ الْغَافِلَاتِ الْمُؤْمِنَاتِ لُعِنُوا فِي الدُّنْيَا وَالْآخِرَةِ وَلَهُمْ عَذَابٌ عَظِيمٌ
Quran's Tafhim ( explanation)
*21) The word ghafilat as used in the Text means the women who are simple, unpretentious souls, who do not know any artifice, who have pious hearts and have no idea of immorality. They cannot even imagine that their names could ever be associated with any slander. The Holy Prophet has said: "To slander chaste women is one of the seven 'deadly' sins." According to another Tradition cited by Tabarani from Hadrat Huzaifah, the Holy Prophet said: "To slander a pious woman suffiices to ruin the good deeds of a hundred years. "