Hadith on Bloodshed: The Son of Adam, Cain, shares the burden of every murder because he started the practice of unlawful killing

Abdullah ibn Mas’ud reported: The Messenger of Allah صلى الله عليه وسلم said, “No person is wrongfully killed except that some of the burden falls upon the son of Adam, because he was the first to establish the practice of murder.”
[Sunan At-Tirmidhi, Book 39, Number 2673, Grade: Sahih]

عَنْ عَبْدِ اللَّهِ بْنِ مَسْعُودٍ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مَا مِنْ نَفْسٍ تُقْتَلُ ظُلْمًا إِلَّا كَانَ عَلَى ابْنِ آدَمَ كِفْلٌ مِنْ دَمِهَا وَذَلِكَ لِأَنَّهُ أَوَّلُ مَنْ أَسَنَّ الْقَتْلَ

قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ

سنن الترمذي كتاب العلم باب ما جاء الدال على الخير كفاعله