Musannaf Ibn Abi Shayba 36:250

Muhammad ibn Marwan narrated to us, from ‘Umarah ibn Abi Hafsah, from ‘Ikrimah, who said: The Prophet (peace and blessings of Allah be upon him) was wounded in his face on the day of Uhud, his incisor tooth was broken, and he became parched from thirst until he began to fall onto his knees, and his companions left him. Then Ubayy ibn Khalaf came, seeking him to avenge the blood of his brother, Umayyah ibn Khalaf. He said, "Where is this one who claims that he is a prophet? Let him come out to me, for if he were a prophet, he would kill me." The Messenger of Allah (peace and blessings of Allah be upon him) said, "Give me the spear." They said, "O Messenger of Allah, and you have the strength [to do so]?" He said, "I have indeed sought from Allah [the power to shed] his blood." He took the spear, then walked toward him and stabbed him, causing him to fall from his mount. His companions carried him away and rescued him. They said to him, "We do not see any harm upon you." He said, "He has indeed sought from Allah [the power to shed] my blood. I feel [the pain of] it to such an extent that if it were upon [the tribes of] Rabi'ah and Mudar, it would have consumed them."