It has been narrated on the authority of Jabir that the Messenger of Allah (ﷺ) said:

Who will kill Ka'b b. Ashraf? He has maligned Allah, the Exalted, and His Messenger. Muhammad b. Maslama said: Messenger of Allah, do you wish that I should kill him? He said: Yes. He said: Permit me to talk (to him in the way I deem fit). He said: Talk (as you like). So, Muhammad b. Maslama came to Ka'b and talked to him, referred to the old friendship between them and said: This man (i. e. the Holy Prophet) has made up his mind to collect charity (from us) and this has put us to a great hardship. When be heard this, Ka'b said: By God, you will be put to more trouble by him. Muhammad b. Maslama said: No doubt, now we have become his followers and we do not like to forsake him until we see what turn his affairs will take. I want that you should give me a loan. He said: What will you mortgage? He said: What do you want? He said: Pledge me your women. He said: You are the most handsome of the Arabs; should we pledge our women to you? He said: Pledge me your children. He said: The son of one of us may abuse us saying that he was pledged for two wasqs of dates, but we can pledge you (cur) weapons. He said: All right. Then Muhammad b. Maslama promised that he would come to him with Harith, Abu 'Abs b. Jabr and Abbad b. Bishr. So they came and called upon him at night. He came down to them. Sufyan says that all the narrators except 'Amr have stated that his wife said: I hear a voice which sounds like the voice of murder. He said: It is only Muhammad b. Maslama and his foster-brother, Abu Na'ila. When a gentleman is called at night even it to be pierced with a spear, he should respond to the call. Muhammad said to his companions: As he comes down, I will extend my hands towards his head and when I hold him fast, you should do your job. So when he came down and he was holding his cloak under his arm, they said to him: We sense from you a very fine smell. He said: Yes, I have with me a mistress who is the most scented of the women of Arabia. He said: Allow me to smell (the scent on your head). He said: Yes, you may smell. So he caught it and smelt. Then he said: Allow me to do so (once again). He then held his head fast and said to his companions: Do your job. And they killed him.