Musannaf Ibn Abi Shayba 36:345

Hawdha ibn Khalifa narrated to us, he said: ‘Awf narrated to us, from Maymun Abu ‘Abd Allah, from ‘Abd Allah ibn Burayda al-Ansari al-Aslami, from his father, who said: When the Messenger of Allah (may Allah bless him and grant him peace) arrived at the vicinity of Khaybar, the people of Khaybar were alarmed and said: "Muhammad has come with the people of Yathrib." He said: The Messenger of Allah (may Allah bless him and grant him peace) sent ‘Umar ibn al-Khattab with the people. He met the people of Khaybar, and they repelled him and forced him and his companions to retreat. They returned to the Messenger of Allah (may Allah bless him and grant him peace), with him accusing his companions of cowardice and his companions accusing him of cowardice. He said: The Messenger of Allah (may Allah bless him and grant him peace) said: "I will certainly give the banner tomorrow to a man who loves Allah and His Messenger, and whom Allah and His Messenger love." He said: When the next day came, Abu Bakr and ‘Umar presented themselves for it. He said: So he called for ‘Ali, and he was suffering from an eye ailment that day, so he spat into his eye and gave him the banner. He said: He set out with the people. He said: He met the people of Khaybar and met Marhab al-Khaybari, who was reciting rajaz poetry and saying: "Khaybar knows that I am Marhab, fully armed, a tested hero. When the lions approach, blazing, I stab sometimes and strike sometimes." He said: He and ‘Ali met, and he struck him a blow on the crown of his head with the sword, and the sword bit into it down to the molars, and the people of the camp heard the sound of his strike. He said: The last of the people had not yet finished [their arrival] before the first of them had already achieved victory.