[Machine] That Ka'b ibn al-Ashraf, the Jewish poet, used to mock the Messenger of Allah ﷺ and his companions and incite against them. He said, "Who will rid me of Ka'b?" When he refused to stop harming the Messenger of Allah ﷺ and the Muslims, the Messenger of Allah ﷺ ordered Sa'd ibn Mu'adh, Muhammad ibn Maslama, and Abu 'Isa ibn al-Harith ibn Abi Is'haq to assassinate him. So they went to Ka'b and mentioned the same.  

أَنَّ كَعْبَ بْنَ الْأَشْرَفِ الْيَهُودِيَّ كَانَ شَاعِرًا وَكَانَ يَهْجُو رَسُولَ اللهِ ﷺ وَأَصْحَابَهُ وَيُحَرِّضُ عَلَيْهِمْ فَقَالَ «مَنْ لِكَعْبٍ؟» فَلَمَّا أَبَى أَنْ يَنْزِعَ عَنْ أَذَى رَسُولِ اللهِ ﷺ وَأَذَى الْمُسْلِمِينَ أَمَرَ رَسُولُ اللهِ ﷺ سَعْدَ بْنَ مُعَاذٍ وَمُحَمَّدَ بْنَ مَسْلَمَةَ وَأَبَا عِيسَى بْنَ الْحَارِثِ ابْنَ أَخِي سَعْدِ بْنِ مُعَاذٍ فِي خَمْسَةٍ فَأَتَوْا كَعْبًا فَذَكَرَ مِثْلَهُ