Ka'b bin Al-Ashraf was a Jewish leader who incited the disbelievers against the Prophet and instigated against the Messenger of Allah. The Prophet asked who can kill him and Masalamah r.a. and Abu Naila r.a. killed him.

FROM BUKHARI VOLUME 5, #369
"Narrated Jabir Abdullah: "Allah's messenger said "Who is willing to kill Ka'b bin Al-Ashraf who has hurt Allah and His apostle?" Thereupon Maslama got up saying, "O Allah's messenger! Would you like that I kill him?" The prophet said, "Yes". Maslama said, "Then allow me to say a (false) thing (i.e. to deceive Ka'b). The prophet said, "You may say it."

Maslama went to Ka'b and said, "That man (i.e. Muhammad) demands Sadaqa (i.e. Zakat) [taxes] from us, and he has troubled us, and I have come to borrow something from you." On that, Ka'b said, "By Allah, you will get tired of him!" Maslama said, "Now as we have followed him, we do not want to leave him unless and until we see how his end is going to be. Now we want you to lend us a camel load or two of food." Ka'b said, "Yes, but you should mortgage something to me." Maslama and his companion said, What do you want?" Ka'b replied, "Mortgage your women to me." They said, "How can we mortgage our women to you and you are the most handsome of the Arabs?" Ka'b said, "Then mortgage your sons to me." They said, "How can we mortgage our sons to you? Later they would be abused by the people's saying that so and so has been mortgaged for a camel load of food. That would cause us great disgrace, but we will mortgage our arms to you."

Maslama and his companion promised Ka'b that Maslama would return to him. He came to Ka'b at night along with Ka'b's foster brother, Abu Naila. Ka'b invited them to come into his fort and then he went down to them. His wife asked him, "Where are you going at this time?" Ka'b replied, None but Maslama and my (foster) brother Abu Naila have come." His wife said, "I hear a voice as if blood is dropping from him." Ka'b said, "They are none by my brother Maslama and my foster brother Abu Naila. A generous man should respond to a call at night even if invited to be killed.

Maslama went with two men. So Maslama went in together with two men, and said to them, "When Ka'b comes, I will touch his hair and smell it, and when you see that I have got hold of his head, strike him. I will let you smell his head."

Ka'b bin Al-Ashraf came down to them wrapped in his clothes, and diffusing perfume. Maslama said, "I have never smelt a better scent than this." Ka'b replied, "I have got the best Arab women who know how to use the high class of perfume." Maslama requested Ka'b "Will you allow me to smell your head?" Ka'b said "yes." Maslama smelt it and made his companions smell it as well. Then he requested Ka'b again, "Will you let me (smell your head)?" Ka'b said "Yes". When Maslama got a strong hold of him, he said (to his companions) "Get at him!" So they killed him and went to the prophet and informed him."

Ahsanti, nice one sis, i beleive the next question is yours.

The companions that went with ka3ab were: 3abbaad bin bishr,salkan bin maslamah (ka3abs foster brother) and al-harith bin aws (his the one that got injured by the sword, after returning to the prophet he alayhi salaatu wassalaam put his saliva on al-hariths wound and it healed on the spot) and lastly 3abs bin 7ibr.

in Bay3atul Aqabah Thaani, there were 73 men and 2 women. Who were the two women who gave the pledge to the Prophet that day?

salamz

the two women Nusaibah bint Ka‘b from the Najjars and Asma’ bint ‘Amr from Bani Salamah