Musnad Ahmad 32:1072

Bahz narrated to us, and Hashim narrated to us, they said: Sulayman ibn al-Mughirah narrated to us, from Thabit, who said: Anas, my uncle—Hashim said: Anas ibn al-Nadr—who I was named after, said: He did not witness the day of Badr with the Prophet, may Allah bless him and grant him peace. He said: This weighed heavily upon him, and he said: "In the first battle the Messenger of Allah, may Allah bless him and grant him peace, witnessed, I was absent from it. If Allah shows me a battle hereafter with the Messenger of Allah, may Allah bless him and grant him peace, Allah shall surely see what I will do." He said: He feared to say anything else. He said: So he witnessed the day of Uhud with the Messenger of Allah, may Allah bless him and grant him peace. He said: He encountered Sa'd ibn Mu'adh, and Anas said to him: "O Abu 'Amr, where are you going?" He said: "Oh, the scent of Paradise! I find it before Uhud." He said: So he fought them until he was killed. There were found on his body more than eighty wounds from sword strikes, spear thrusts, and arrow shots. He said: His sister, my aunt al-Rubayyi' bint al-Nadr, said: "I did not recognize my brother except by his fingertips." And 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]. And they did not alter [the terms of their commitment] by any alteration" [Al-Ahzab: 23]. He said: They used to believe that it was revealed concerning him and his companions.