Qur'an 24:2

ٱلزَّانِيَةُ وَٱلزَّانِى فَٱجْلِدُوا۟ كُلَّ وَٰحِدٍ مِّنْهُمَا مِا۟ئَةَ جَلْدَةٍ ۖ وَلَا تَأْخُذْكُم بِهِمَا رَأْفَةٌ فِى دِينِ ٱللَّهِ إِن كُنتُمْ تُؤْمِنُونَ بِٱللَّهِ وَٱلْيَوْمِ ٱلْـَٔاخِرِ ۖ وَلْيَشْهَدْ عَذَابَهُمَا طَآئِفَةٌ مِّنَ ٱلْمُؤْمِنِينَ

“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 [i.e., law] of Allāh, if you should believe in Allāh and the Last Day. And let a group of the believers witness their punishment.”

An-Noor 24:2 · Saheeh International