The sin of illegal sexual intercourse
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، أَخْبَرَنَا إِسْحَاقُ بْنُ يُوسُفَ، أَخْبَرَنَا الْفُضَيْلُ بْنُ غَزْوَانَ، عَنْ عِكْرِمَةَ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " لاَ يَزْنِي الْعَبْدُ حِينَ يَزْنِي وَهْوَ مُؤْمِنٌ، وَلاَ يَسْرِقُ حِينَ يَسْرِقُ وَهْوَ مُؤْمِنٌ، وَلاَ يَشْرَبُ حِينَ يَشْرَبُ وَهْوَ مُؤْمِنٌ، وَلاَ يَقْتُلُ وَهْوَ مُؤْمِنٌ ". قَالَ عِكْرِمَةُ قُلْتُ لاِبْنِ عَبَّاسٍ كَيْفَ يُنْزَعُ الإِيمَانُ مِنْهُ قَالَ هَكَذَا ـ وَشَبَّكَ بَيْنَ أَصَابِعِهِ ثُمَّ أَخْرَجَهَا ـ فَإِنْ تَابَ عَادَ إِلَيْهِ هَكَذَا وَشَبَّكَ بَيْنَ أَصَابِعِهِ
Narrated 'Ikrima from Ibn 'Abbas: Allah's Messengers 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.