Sahih al-Bukhari 6810
Sahih al-Bukhari · Book 86: Limits and Punishments set by Allah (Hudood) · The sin of illegal sexual intercourse
Narrated Abu Huraira:
حَدَّثَنَا آدَمُ ، حَدَّثَنَا شُعْبَةُ ، عَنِ الأَعْمَشِ ، عَنْ ذَكْوَانَ ، عَنْ أَبِي هُرَيْرَةَ ، قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم " لاَ يَزْنِي الزَّانِي حِينَ يَزْنِي وَهْوَ مُؤْمِنٌ، وَلاَ يَسْرِقُ حِينَ يَسْرِقُ وَهْوَ مُؤْمِنٌ، وَلاَ يَشْرَبُ حِينَ يَشْرَبُهَا وَهْوَ مُؤْمِنٌ، وَالتَّوْبَةُ مَعْرُوضَةٌ بَعْدُ " .
The Prophet (ﷺ) said, "The one who commits an illegal sexual intercourse is not a believer at the time of committing illegal sexual intercourse and a thief is not a believer at the time of committing theft and a drinker of alcoholic drink is not a believer at the time of drinking. Yet, (the gate of) repentance is open thereafter."