The Prophet ﷺ said, "Who is ready to kill Kaʿb bin Al-Ashraf who has really hurt Allah and His Apostle?" Muhammad bin Maslama said, "O Messenger of Allah ﷺ! Do you like me to kill him?" He replied in the affirmative. So, Muhammad bin Maslama went to him (i.e. Kaʿb) and said, "This person (i.e. the Prophet) has put us to task and asked us for charity." Kaʿb replied, "By Allah, you will get tired of him." Muhammad said to him, "We have followed him, so we dislike to leave him till we see the end of his affair." Muhammad bin Maslama went on talking to him in this way till he got the chance to kill him.  

أَنَّ النَّبِيَّ ﷺ قَالَ مَنْ لِكَعْبِ بْنِ الأَشْرَفِ فَإِنَّهُ قَدْ آذَى اللَّهَ وَرَسُولَهُ قَالَ مُحَمَّدُ بْنُ مَسْلَمَةَ أَتُحِبُّ أَنْ أَقْتُلَهُ يَا رَسُولَ اللَّهِ قَالَ نَعَمْ قَالَ فَأَتَاهُ فَقَالَ إِنَّ هَذَا يَعْنِي النَّبِيَّ ﷺ قَدْ عَنَّانَا وَسَأَلَنَا الصَّدَقَةَ قَالَ وَأَيْضًا وَاللَّهِ قَالَ فَإِنَّا قَدِ اتَّبَعْنَاهُ فَنَكْرَهُ أَنْ نَدَعَهُ حَتَّى نَنْظُرَ إِلَى مَا يَصِيرُ أَمْرُهُ قَالَ فَلَمْ يَزَلْ يُكَلِّمُهُ حَتَّى اسْتَمْكَنَ مِنْهُ فَقَتَلَهُ