[Machine] That Harith ibn Zaid was hostile towards the Prophet ﷺ , then he embraced Islam and Ayyash did not realize it. Ayyash ibn Abi Rabiah met him and attacked him, killing him. Allah revealed the verse: "And never should a believer kill another believer except by mistake." This was narrated from the hadith of Jabir ibn Abdullah, and it was connected. Ash-Shafi'i said, "Allah perfected the revelation of His book by stating that the killer of a believer must pay blood money to the family." The Prophet ﷺ also clarified the amount of the blood money.  

أَنَّ الْحَارِثَ بْنَ زَيْدٍ كَانَ شَدِيدًا عَلَى النَّبِيِّ ﷺ فَجَاءَ إِلَى الْإِسْلَامِ وَعَيَّاشٌ لَا يَشْعُرُ فَلَقِيَهُ عَيَّاشُ بْنُ أَبِي رَبِيعَةَ فَحَمَلَ عَلَيْهِ فَقَتَلَهُ فَأَنْزَلَ اللهُ ﷻ {وَمَا كَانَ لِمُؤْمِنٍ أَنْ يَقْتُلَ مُؤْمِنًا إِلَّا خَطَأً} الْآيَةَ وَقَدْ رُوِّينَاهُ مِنْ حَدِيثِ جَابِرِ بْنِ عَبْدِ اللهِ مَوْصُولًا قَالَ الشَّافِعِيُّ فَأَحْكَمَ اللهُ فِي تَنْزِيلِ كِتَابِهِ أَنَّ عَلَى قَاتِلِ الْمُؤْمِنِ دِيَةً مُسَلَّمَةً إِلَى أَهْلِهِ وَأَبَانَ عَلَى لِسَانِ نَبِيِّهِ ﷺ كَمَّ الدِّيَةِ