The sin of illegal sexual intercourse

Narrated 'Ikrima from Ibn 'Abbas:

Allah's Apostles said, "When a slave (of Allah) commits illegal sexual intercourse, he is not a believer at the time of committing it;
and if he steals, he is not a believer at the time of stealing;
and if he drinks an alcoholic drink, when he is not a believer at the time of drinking it;
and he is not a believer when he commits a murder," 'Ikrima said: I asked Ibn Abbas, "How is faith taken away from him?" He said, Like this," by clasping his hands and then separating them, and added, "But if he repents, faith returns to him like this, by clasping his hands again.

أَخْبَرَنَا دَاوُدُ بْنُ شَبِيبٍ، حَدَّثَنَا هَمَّامٌ، عَنْ قَتَادَةَ، أَخْبَرَنَا أَنَسٌ، قَالَ لأُحَدِّثَنَّكُمْ حَدِيثًا لاَ يُحَدِّثُكُمُوهُ أَحَدٌ بَعْدِي، سَمِعْتُهُ مِنَ النَّبِيِّ ﷺ سَمِعْتُ النَّبِيَّ ﷺ يَقُولُ " لاَ تَقُومُ السَّاعَةُ ـ وَإِمَّا قَالَ مِنْ أَشْرَاطِ السَّاعَةِ ـ أَنْ يُرْفَعَ الْعِلْمُ وَيَظْهَرَ الْجَهْلُ، وَيُشْرَبَ الْخَمْرُ، وَيَظْهَرَ الزِّنَا، وَيَقِلَّ الرِّجَالُ، وَيَكْثُرَ النِّسَاءُ، حَتَّى يَكُونَ لِلْخَمْسِينَ امْرَأَةً الْقَيِّمُ الْوَاحِدُ ".

Narrated Abu Huraira:

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."

حَدَّثَنَا آدَمُ، حَدَّثَنَا شُعْبَةُ، عَنِ الأَعْمَشِ، عَنْ ذَكْوَانَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ النَّبِيُّ ﷺ " لاَ يَزْنِي الزَّانِي حِينَ يَزْنِي وَهْوَ مُؤْمِنٌ، وَلاَ يَسْرِقُ حِينَ يَسْرِقُ وَهْوَ مُؤْمِنٌ، وَلاَ يَشْرَبُ حِينَ يَشْرَبُهَا وَهْوَ مُؤْمِنٌ، وَالتَّوْبَةُ مَعْرُوضَةٌ بَعْدُ ".