"It is not permissible to kill a Muslim except in one of three cases: A adulterer who has been married, who is to be stoned; a man who kills a Muslim deliberately; and a man who leaves Islam and wages war against Allah, the Mighty and Sublime, and His Messenger, who is to be killed, crucified or banished from the land."  

عَنْ رَسُولِ اللَّهِ ﷺ أَنَّهُ قَالَ لاَ يَحِلُّ قَتْلُ مُسْلِمٍ إِلاَّ فِي إِحْدَى ثَلاَثِ خِصَالٍ زَانٍ مُحْصَنٍ فَيُرْجَمُ وَرَجُلٌ يَقْتُلُ مُسْلِمًا مُتَعَمِّدًا وَرَجُلٌ يَخْرُجُ مِنَ الإِسْلاَمِ فَيُحَارِبُ اللَّهَ ﷻ وَرَسُولَهُ فَيُقْتَلُ أَوْ يُصَلَّبُ أَوْ يُنْفَى مِنَ الأَرْضِ  

The Messenger of Allah [SAW] said: "It is not permissible to shed the blood of a Muslim except in three cases: An adulterer who had been married, who should be stoned to death; a man who killed another man intentionally, who should be killed; and a man who left Islam and waged war against Allah, the Might and Sublime, and His Messenger, who should be killed, or crucified, or banished from the land."  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ لاَ يَحِلُّ دَمُ امْرِئٍ مُسْلِمٍ إِلاَّ بِإِحْدَى ثَلاَثِ خِصَالٍ زَانٍ مُحْصَنٌ يُرْجَمُ أَوْ رَجُلٌ قَتَلَ رَجُلاً مُتَعَمِّدًا فَيُقْتَلُ أَوْ رَجُلٌ يَخْرُجُ مِنَ الإِسْلاَمِ يُحَارِبُ اللَّهَ ﷻ وَرَسُولَهُ فَيُقْتَلُ أَوْ يُصْلَبُ أَوْ يُنْفَى مِنَ الأَرْضِ