Sunan an-Nasa'i 4057
سنن النسائي#4057Sahihأَخْبَرَنَا أَبُو الأَزْهَرِ، أَحْمَدُ بْنُ الأَزْهَرِ النَّيْسَابُورِيُّ قَالَ حَدَّثَنَا إِسْحَاقُ بْنُ سُلَيْمَانَ الرَّازِيُّ، قَالَ أَنْبَأَنَا الْمُغِيرَةُ بْنُ مُسْلِمٍ، عَنْ مَطَرٍ الْوَرَّاقِ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ عُثْمَانَ، قَالَ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " لاَ يَحِلُّ دَمُ امْرِئٍ مُسْلِمٍ إِلاَّ بِإِحْدَى ثَلاَثٍ رَجُلٌ زَنَى بَعْدَ إِحْصَانِهِ فَعَلَيْهِ الرَّجْمُ أَوْ قَتَلَ عَمْدًا فَعَلَيْهِ الْقَوَدُ أَوِ ارْتَدَّ بَعْدَ إِسْلاَمِهِ فَعَلَيْهِ الْقَتْلُ " .
It was narrated from Ibn 'Umar that:'Uthman said: "I heard the Messenger of Allah [SAW] say: 'It is not permissible to shed the blood of a Muslim except in three cases: A man who commits adultery after having married; or one who kills intentionally, in which case he deserves retaliation; or one who apostatizes after having become Muslim, in which case he deserves to be killed
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 37:92