24:4
وَالَّذِينَ يَرْمُونَ الْمُحْصَنَاتِ ثُمَّ لَمْ يَأْتُوا بِأَرْبَعَةِ شُهَدَاءَ فَاجْلِدُوهُمْ ثَمَانِينَ جَلْدَة ً وَلاَ تَقْبَلُوا لَهُمْ شَهَادَةً أَبَدا ً وَأُوْلَائِكَ هُمُ الْفَاسِقُونَ
Wa Al-Ladhīna Yarmūna Al-Muĥşanāti Thumma Lam Ya'tū Bi'arba`ati Shuhadā'a Fājlidūhum Thamānīna Jaldatan Wa Lā Taqbalū Lahum Shahādatan 'Abadāan Wa' Ūlā'ika Humu Al-Fāsiqūna 

And those who accuse the independent females, then they do not bring forth four witnesses, you shall lash them with eighty lashes, and do not accept their testimony ever; and those are the wicked.