The Prophet ﷺ said, "Who is ready to kill Kaʿb bin Ashraf (i.e. a Jew)." Muhammad bin Maslama replied, "Do you like me to kill him?" The Prophet ﷺ replied in the affirmative. Muhammad bin Maslama said, "Then allow me to say what I like." The Prophet ﷺ replied, "I do (i.e. allow you).  

عَنِ النَّبِيِّ ﷺ قَالَ مَنْ لِكَعْبِ بْنِ الأَشْرَفِ فَقَالَ مُحَمَّدُ بْنُ مَسْلَمَةَ أَتُحِبُّ أَنْ أَقْتُلَهُ قَالَ نَعَمْ قَالَ فَأْذَنْ لِي فَأَقُولَ قَالَ قَدْ فَعَلْتُ