It was narrated from 'Ikrimah, from Ibn 'Abbas, that :
the Prophet ﷺ set the blood money at twelve thousand (Dirham). He said: “This is what Allah says: 'And they could not find any cause to do so except that Allah and his Messenger ﷺ had enriched them of His bounty.'” He said: “By their taking the blood money.”

حَدَّثَنَا الْعَبَّاسُ بْنُ جَعْفَرٍ، حَدَّثَنَا مُحَمَّدُ بْنُ سِنَانٍ، حَدَّثَنَا مُحَمَّدُ بْنُ مُسْلِمٍ، عَنْ عَمْرِو بْنِ دِينَارٍ، عَنْ عِكْرِمَةَ، عَنِ ابْنِ عَبَّاسٍ، أَنَّ النَّبِيَّ ﷺ جَعَلَ الدِّيَةَ اثْنَىْ عَشَرَ أَلْفًا قَالَ ذَلِكَ قَوْلُهُ {وَمَا نَقَمُوا إِلاَّ أَنْ أَغْنَاهُمُ اللَّهُ وَرَسُولُهُ مِنْ فَضْلِهِ} قَالَ بِأَخْذِهِمُ الدِّيَةَ .