An-Nur 24:2

ٱلزَّانِيَةُ وَٱلزَّانِي فَٱجۡلِدُواْ كُلَّ وَٰحِدٖ مِّنۡهُمَا مِاْئَةَ جَلۡدَةٖۖ وَلَا تَأۡخُذۡكُم بِهِمَا رَأۡفَةٞ فِي دِينِ ٱللَّهِ إِن كُنتُمۡ تُؤۡمِنُونَ بِٱللَّهِ وَٱلۡيَوۡمِ ٱلۡأٓخِرِۖ وَلۡيَشۡهَدۡ عَذَابَهُمَا طَآئِفَةٞ مِّنَ ٱلۡمُؤۡمِنِينَ 2

The [unmarried] woman or [unmarried] man found guilty of sexual intercourse - lash each one of them with a hundred lashes, and do not be taken by pity for them in the religion of Allah, if you should believe in Allah and the Last Day. And let a group of the believers witness their punishment