I reached Medina and presented myself before the Messenger of Allah ﷺ. He said, “Wahshi?” I replied, “Yes.” He said, “Sit down and tell me how you killed Hamzah.” So I narrated it to him exactly as I have just related it to you two. Thereupon he said, “Woe to you! Keep your face away from me; do not let me see you again.” From that day on I deliberately avoided the Messenger of Allah ﷺ wherever he might be (1) until he passed away.
When the Muslims marched out against Musaylima, I went with them, carrying the very spear with which I had killed Hamzah. When the two armies met, I looked for Musaylima and saw him holding a sword. By Allah, I could not even recognize him, and at the same time an Ansari was advancing on him from another direction—both of us were seeking him. When he came within my reach, I drove my spear into him and it struck him, and the Ansari closed in and struck him with his sword. Your Lord knows best which of us killed him.
If it was I who killed him, then I have killed the best of men after the Messenger of Allah ﷺ and I have killed the worst of men (2).
With this same chain: from Sulayman ibn Yasar, from Abdullah ibn Umar, who said: I heard a man say, “The black slave killed him”—meaning Musaylima.