Musnad Abu Ya'la al-Mawsili 252:35

Yahya ibn Ayyub narrated to us, Sa'id ibn 'Abd al-Rahman al-Qadi narrated to us, from Abu Hazim, from Sahl ibn Sa'd, that he said: "O Messenger of Allah, on the day of Uhud, we did not see the likes of what so-and-so did. A man came to him; the people fled, but he did not flee. He did not leave a single one of the polytheists, neither a straggler nor a solitary one, but that he pursued them, striking them with his sword." He [the Prophet] said: "And who is he?" He [Sahl] said: "So he attributed his lineage to the Messenger of Allah, may Allah bless him and grant him peace, but he did not recognize him. Then he described him by his attributes, but he did not recognize him, until the man appeared in person. He said: 'Is this the one, O Messenger of Allah, whom we told you about?' He said: 'This one?' They said: 'Yes.' He said: 'He is of the people of the Fire.'" He said: "That was severe upon the Muslims. They said: 'And who among us is of the people of Paradise if so-and-so is of the people of the Fire?' A man from the people said: 'O people, watch me. By the One in whose hand is my soul, he will not die upon the state he is in this morning, and I shall be his companion among you.' Then he went forth with his utmost effort the next day. The man would charge when he charged, and retreat when he retreated, watching what his affair would lead to, until he was struck by a wound that incapacitated him. He sought to hasten his death, so he placed the hilt of his sword on the ground and placed its tip between his breasts, then he leaned upon his sword until it came out of his back." The man went running and said: "I bear witness that there is no god but Allah, and I bear witness that you are the Messenger of Allah." He stood before the Messenger of Allah, may Allah bless him and grant him peace, and said: "And that, what is it?" He said: "O Messenger of Allah, the man who was mentioned to you, and you said he is of the people of the Fire, and that was severe upon the Muslims, and they said: 'Who among us is of the people of Paradise if so-and-so is of the people of the Fire?' So I said: 'O people, watch me. By the One in whose hand is my soul, he will not die upon the state he is in this morning, and I shall be his companion among you.' So I began to charge with him when he charged, and retreat with him when he retreated, and I watched what his affair would lead to, until he was struck by a wound that incapacitated him. He sought to hasten his death, so he placed the hilt of his sword on the ground and placed its tip between his breasts, then he leaned upon his sword until it came out from between his back." "He is that one, O Messenger of Allah, writhing in his agony." The Messenger of Allah, may Allah bless him and grant him peace, said: "Indeed, a man may perform the deeds of the people of Paradise, as it appears to the people, while he is of the people of the Fire; and a man may perform the deeds of the people of the Fire, as it appears to the people, while he is of the people of Paradise."