Historians have given different descriptions about the incident of killing Marhab. According to
Sahih Muslim, Ali went to meet Marhab in a single combat. Marhab advanced brandishing his sword and chanting: "Khaybar knows certainly that I am Marhab, a fully armed and well-tried valorous warrior (hero) when war comes spreading its flames". Ali chanted in reply: I am the one whose mother named him Haydar, (synonym of lion) like a lion of the forest with a terror-striking countenance". The narrator said: Ali struck at the head of Marhab and killed him, so the victory (capture of Khaibar) was due to him.
Al-Maqrizi recorded: "The Ansari reported that he saw Marhab's mother holding his dead body and weeping". According the book
History of Islam Vol. 1, when Ali hit Marhab bin Al-Harith on the head, the strike was as strong as it cut the body of Marhab in two equal pieces. All the soldiers left the battlefield henceforth and the battle was won by the Muslims.
Sirah Ibn-Hisham claims that,
Muhammad ibn Maslama killed Marhab. On the first day of the battle his brother Mahmud was fatally injured while he was sitting in the shade of Fort Na'im. Inside the fortress, the Jewish warrior Marhab threw down a millstone, which landed on Mahmud's head. It took Mahmud three days to die, during this time, Ibn Maslamah promised to take care of his brother's daughters. The battle ended with Ibn Maslamah managing to chop off one of Marhab's legs. ==References==