Surah An-Nur (The Light), Verse 4

وَالَّذِیْنَ یَرْمُوْنَ الْمُحْصَنٰتِ ثُمَّ لَمْ یَاْتُوْا بِاَرْبَعَةِ شُهَدَآءَ فَاجْلِدُوْهُمْ ثَمٰنِیْنَ جَلْدَةً وَّلَا تَقْبَلُوْا لَهُمْ شَهَادَةً اَبَدًا وَاُولٰٓىِٕكَ هُمُ الْفٰسِقُوْنَ ۟

Wallazeena yarmoonal muhsanaati summa lam yaatoo bi-arba'ati shuhadaaa'a fajlidoohum samaaneena jaldatanw wa laa taqbaloo lahum shahaadatan abadaa; wa ulaaa'ika humul faasiqoon

“And those who launch a charge against chaste women, and produce not four witnesses (to support their allegations),- flog them with eighty stripes; and reject their evidence ever after: for such men are wicked transgressors;-”

Quran 24:4 (Yusuf Ali Translation)