Musannaf Ibn Abi Shaybah 30869 — What protects blood and spares a man

Abu Zabyan said: Sayyiduna Usamah (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) sent us with a military detachment, and we attacked al-Huruqat of the tribe of Juhaynah in the morning. I came upon a man, and he said: La ilaha illa Allah (there is no god but Allah). Then I stabbed him with a spear. After that, unease arose in my heart about it, so I mentioned this to the Prophet (peace and blessings be upon him), and the Messenger of Allah (peace and blessings be upon him) said: He recited La ilaha illa Allah, and you still killed him? I said: O Messenger of Allah (peace and blessings be upon him)! He only recited this statement out of fear of the weapon! He (peace and blessings be upon him) said: Why did you not split open his heart, so that you would have known whether he recited this statement out of fear or not? He said: He (peace and blessings be upon him) kept repeating this to me until I wished that I had accepted Islam only on that day.