عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ: أَنَّ عُمَرَ بْنَ الْخطاب قَتَلَ نَفَرًا خَمْسَةً أَوْ سَبْعَةً بِرَجُلٍ وَاحِدٍ قَتَلُوهُ قَتْلَ غِيلَةٍ وَقَالَ عُمَرُ: لَوْ تَمَالَأَ عَلَيْهِ أَهْلُ صَنْعَاءَ لَقَتَلْتُهُمْ جَمِيعًا. رَوَاهُ مَالِكٌ وروى البُخَارِيّ عَن ابْن عمر نَحوه

Abu Huraira reported God’s Messenger as saying, “If anyone helps in killing a believer to the extent of half a word,* he will meet God with ‘Despairing of God’s mercy’ written on his forehead.” Ibn Majah transmitted it.* This is taken to mean that it is a serious matter even to utter half the word which expresses an intention to kill a believer.