Musnad Ahmad 276:1

Hujayn ibn al-Muthanna Abu Umar narrated to us, he said: Abd al-Aziz—meaning Ibn Abd Allah ibn Abi Salamah—narrated to us, from Abd Allah ibn al-Fadl, from Sulayman ibn Yasar, from Ja’far ibn Amr al-Damri, who said: I went out with Ubayd Allah ibn Adi ibn al-Khiyar to al-Sham. When we arrived in Homs, Ubayd Allah said to me: "Do you wish to go to Wahshi so we may ask him about the killing of Hamza?" I said: "Yes." Wahshi used to live in Homs. He said: So we asked about him, and it was said to us: "He is that one in the shade of his palace, as if he were a *hamit* (a water skin)." He said: So we came until we stood before him, and we greeted him, and he returned the greeting to us. He said: Ubayd Allah was wrapped in his turban, and Wahshi could see nothing of him except his eyes and his feet. Ubayd Allah said: "O Wahshi, do you recognize me?" He said: He looked at him, then said: "No, by Allah, except that I know that Adi ibn al-Khiyar married a woman called Umm Qital, daughter of Abi al-Is. She bore him a boy in Mecca, and he sought a wet nurse for him. I carried that boy with his mother, and I handed him to her. It is as if I am looking at your feet." He said: Ubayd Allah uncovered his face and said: "Will you not tell us about the killing of Hamza?" He said: "Yes. Hamza killed Tu’aymah ibn Adi at Badr. My master, Jubayr ibn Mut’im, said to me: 'If you kill Hamza for my uncle, you are free.' When the people went out on the day of ‘Aynayn—he said: and ‘Aynayn is a small mountain beneath Uhud, with a valley between them—I went out with the people to fight. When they lined up for battle, he said: Siba’ went out saying: 'Who will duel?' He said: Hamza ibn Abd al-Muttalib went out to him and said: 'O Siba’, son of Umm Anmar, O son of the one who cuts the clitorises, do you defy Allah and His Messenger?' Then he attacked him, and he was like the day that has passed. I lay in wait for Hamza under a rock until he passed by me. When he drew near to me, I threw my spear at him, placing it in his lower abdomen until it came out between his hips. He said: That was the last I saw of him. He said: When the people returned, I returned with them. He said: I stayed in Mecca until Islam spread there. He said: Then I went out to al-Ta’if. He said: The Messenger of Allah (peace be upon him) sent for me. He said: And it was said to him: 'He does not harm messengers.' He said: So I went out with them until I arrived at the Messenger of Allah (peace be upon him). He said: When he saw me, he said: 'Are you Wahshi?' I said: 'Yes.' He said: 'You killed Hamza?' I said: 'The matter reached you as you have heard, O Messenger of Allah.' He said: 'Can you keep your face hidden from me?' He said: So I left. When the Messenger of Allah (peace be upon him) passed away and Musaylimah the Liar appeared, I said: 'I will go out to Musaylimah, perhaps I will kill him and thereby compensate for Hamza.' He said: So I went out with the people, and their affair was what it was. He said: Suddenly, there was a man standing in a breach of a wall, looking like a dusty-colored camel with his hair disheveled. He said: I threw my spear at him, placing it between his breasts until it came out between his shoulder blades. He said: A man from the Ansar crawled toward him and struck him on the head with his sword." Abd Allah ibn al-Fadl said: Sulayman ibn Yasar informed me that he heard Abd Allah ibn Umar [say]: "A slave girl on the roof of a house said: 'Woe to the Commander of the Faithful, the black slave has killed him.'"