Musannaf Ibn Abi Shayba 36:228

Yazid ibn Harun narrated to us, he said: Humayd informed us, from Anas ibn Malik, that his uncle was absent from the fighting of Badr. He said: "I was absent from the first battle the Messenger of Allah (may Allah bless him and grant him peace) fought against the polytheists. If Allah shows me [another battle], He shall see what I will do." When the day of Uhud came and the Muslims were routed, he said: "O Allah, I apologize to You for what these have done"—meaning the Muslims—"and I disassociate myself from what these have brought"—meaning the polytheists. He advanced, and Sa'd met him at the rear, near Uhud. Sa'd said: "I am with you." He [Anas's uncle] said: "I could not do what he [the Prophet] did." He was found with over eighty wounds from a sword strike, a spear thrust, and an arrow shot. We used to say that regarding him and his companions, this [verse] was revealed: "Among the believers are men true to what they promised Allah. Among them is he who has fulfilled his vow [to the death], and among them is he who awaits [his chance]."