Musnad Abu Ya'la al-Mawsili 133:13

Hadb ibn Khalid narrated to us, Hammad ibn Salamah narrated to us, from Ali ibn Zayd and Thabit, from Anas ibn Malik, that the Messenger of Allah (peace be upon him) said on the day of Uhud, when they (the polytheists) overwhelmed him while he was with seven of the Ansar and two men from others: "Who will repel them from us, and he will be my companion in Paradise?" A man from the Ansar stood up and fought until he was killed. Then he (the Prophet) said the same thing again. Another man stood up and fought until he was killed. He continued to say that until the seven were killed. Then the Messenger of Allah (peace be upon him) said: "Our companions have not treated us fairly."