Surat An-Nisā' - سورة النساء

وَاللَّذَانِ يَأْتِيَانِهَا مِنكُمْ فَآذُوهُمَا ۖ فَإِن تَابَا وَأَصْلَحَا فَأَعْرِضُوا عَنْهُمَا ۗ إِنَّ اللَّهَ كَانَ تَوَّابًا رَّحِيمًا

Muhsin Khan: And the two persons (man and woman) among you who commit illegal sexual intercourse, punish them both. And if they repent (promise Allah that they will never repeat, i.e. commit illegal sexual intercourse and other similar sins) and do righteous good deeds, leave them alone. Surely, Allah is Ever the One Who accepts repentance, (and He is) Most Merciful.