Anas (May Allah be pleased with him) reported:
My uncle Anas bin An- Nadr (May Allah be pleased with him) was absent from the battle of Badr. He said: "O Messenger of Allah! I was absent from the first battle you fought against the pagans. (By Allah!) if Allah gives me a chance to fight against the pagans, no doubt, Allah will see how (bravely) I will fight." On the Day of Uhud, when the Muslims turned their backs and fled, he said, "O Allah! I apologize to You for what these (i.e., his companions) have done, and I denounce what these (i.e., the pagans) have done." Then he advanced and Sa'd bin Mu'adh met him. He said: "O Sa'd bin Mu'adh! By the Rubb of An-Nadr, Jannah! I am smelling its aroma coming from before (the mountain of) Uhud," Later on, Sa'd said: "O Messenger of Allah! I cannot achieve or do what he (i.e., Anas bin An-Nadr) did. We found more than eighty wounds by swords, spears and arrows on his body. We found him dead and his body was mutilated so badly that none except his sister could recognise him by his finger." We used to think that the following Ayah was revealed concerning him and other men of his sort: "Among the believers are men who have been true to their covenant with Allah (i.e., they have gone out for Jihad, and showed not their backs to the disbelievers), of them some have fulfilled their obligations (i.e., have been martyred)." (33:23).
App reference: Book 12, Hadith 33
Arabic/English book reference: Book 12, Hadith 1317