Musannaf Ibn Abi Shayba 36:243

Aswad ibn Amir narrated to us, he said: Hammad ibn Salamah narrated to us, he said: Ali ibn Zayd and Thabit narrated to us, from Anas, that when the polytheists overwhelmed the Prophet, peace and blessings of Allah be upon him, on the day of Uhud, he said: "Whoever repels them from us, he is in Paradise." So a man from the Ansar stood up and fought until he was killed. Then another stood up to repel them until seven were killed. The Prophet, peace and blessings of Allah be upon him, said: "Our companions have not treated us fairly."