Musnad Ahmad 30:971

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from al-Zuhri, from Ibn al-Musayyib, from Abu Hurayrah, who said: We were present with the Messenger of Allah, peace and blessings of Allah be upon him, on the day of Khaybar. He said—meaning to a man who claimed to be a Muslim—: "This one is of the people of the Fire." When we attended the fighting, the man fought a fierce fight and was struck by a wound. It was said: "O Messenger of Allah, the man whom you said was of the people of the Fire has fought a fierce fight today, and he has died." The Prophet, peace and blessings of Allah be upon him, said: "To the Fire." Some of the people almost doubted. While they were in that state, it was said: "He has not died, but he has a severe wound." When night came, he could not endure the wounds, so he killed himself. The Prophet, peace and blessings of Allah be upon him, was informed of that, and he said: "Allah is the Greatest. I bear witness that I am the servant of Allah and His Messenger." Then he ordered Bilal, and he called out among the people: "Indeed, no one shall enter Paradise except a Muslim soul, and indeed Allah supports this religion with the wicked man."