Musannaf Ibn Abi Shayba 19:872

Abu Bakr narrated to us, he said: Shababa bin Sawwar narrated to us, he said: Sulaiman bin al-Mughira narrated to us, from Humayd bin Hilal, he said: Abu al-Aliyah came to me and to a companion of mine and said: "Come, for you two are younger than me, or more retentive of the hadith than me." So we set off until we came to Bishr bin Asim al-Laythi. He said: The Prophet, may Allah bless him and grant him peace, sent a military detachment, and it raided a people. A man from the people fled, and a man from the detachment followed him, having a drawn sword with him. The one fleeing from the people said: "I am a Muslim." But he did not look into what he said, so he struck him and killed him. The hadith reached the Prophet, may Allah bless him and grant him peace, and the Prophet, may Allah bless him and grant him peace, said a harsh statement. It reached the killer. While the Prophet, may Allah bless him and grant him peace, was delivering a sermon, the killer said: "By Allah, O Prophet of Allah, he did not say what he said except to seek refuge from being killed." The Prophet, may Allah bless him and grant him peace, turned away from him and from those of the people who were next to him. He did that twice, and each time the Prophet turned his face away from him. He could not bear it, so he said the same thing a third time. The Prophet, may Allah bless him and grant him peace, turned his face, and displeasure was recognized in his face. He said: "Indeed, Allah has refused for me [to accept the excuse of] one who kills a believer," saying that three times.