Musannaf Ibn Abi Shaybah

It is narrated from Hazrat Ali (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) set out towards Khaybar. When he (peace and blessings be upon him) reached Khaybar, he (peace and blessings be upon him) sent Hazrat Umar and some people with him towards the city or fortress of the people of Khaybar. They went and fought with them. But soon this group of Muslims... Hazrat Umar and his companions... retreated. So Hazrat Umar, blaming his companions and his companions blaming Hazrat Umar for cowardice, returned (to the service of the Prophet, peace and blessings be upon him). The Prophet (peace and blessings be upon him) disliked this and said, "Now I will surely send towards the Jews such a man who loves Allah and His Messenger, and Allah and His Messenger also love him. He will continue to fight with them until Allah grants victory at his hands. He will not be one who flees." (Hearing this) many people became desirous of this and began to stretch their necks, waiting to see whom the Prophet (peace and blessings be upon him) would refer to. The Prophet (peace and blessings be upon him) remained silent for a while, then said: "Where is Ali (may Allah be pleased with him)?" The people said, "He is suffering from an eye ailment." The Prophet (peace and blessings be upon him) said, "Call him to me." When I was brought to the Prophet (peace and blessings be upon him), he (peace and blessings be upon him) opened my eyes and applied his blessed saliva to them. Then he (peace and blessings be upon him) gave me the flag. I took the flag and ran quickly, fearing that the Prophet (peace and blessings be upon him) might have a thought about me or about someone else. Until I reached the enemies and fought with them. Marhab, the Jew, came out reciting boastful verses for single combat, so I too came out reciting boastful verses in response for single combat. Then we clashed, and Allah caused him to be killed at my hands. His companions retreated and took refuge in the fortress; they closed the gate. We reached the gate, and I kept striking the gate until Allah opened it.