رِيَاضُ الصَّالِحِينَ
Riyad as-Salihin 172
The Book of Miscellany
Heretics doing desirable or undesirable deeds
وَعَنِ ابْنِ مَسْعُودٍ رَضِيَ اللَّهُ عَنْهُ أَنَّ النَّبِيِّ صَلَّى اللَّه عَلَيْهِ وَسَلَّمَ قَالَ: لَيْسَ مِنْ نَفْسٍ تُقْتَلُ ظُلْمًا إِلاَّ كَانَ عَلَى ابْنِ آدَمَ الأَوَّلِ كِفْلٌ مِنْ دَمِهَا لأَنَّهُ كَانَ أَوَّلَ مَنْ سَنَّ الْقَتْلَ ((مُتَّفَقٌ عَلَيْهِ)) .
Ibn Mas'ud (May Allah be pleased with him) reported: The Prophet (ﷺ) said, "The first son of Adam* takes a share of the guilt of every one who murders another wrongfully because he was the initiator of committing murder". [Al-Bukhari and Muslim]. * The son of Adam in the Hadith is said to be Qabil. Allah tells us about his story in Surat Al-Ma'idah (The Table spread with Food). Verses 27-31.
Riyad as-Salihin, 172