It is narrated from Hazrat Usama that the Messenger of Allah, peace and blessings be upon him, sent us on an expedition: we encountered a man from the tribe of Juhaina, and he said "La ilaha illallah" (There is no god but Allah). I struck him with a spear. Afterwards, this matter weighed on my heart, so I mentioned it to the Noble Prophet, peace and blessings be upon him. He, peace and blessings be upon him, said: He said "La ilaha illallah" and yet you killed him? The narrator says: I submitted, O Messenger of Allah, peace and blessings be upon him! He only said this out of fear of the weapon. He, peace and blessings be upon him, said: Why did you not cut open his heart so that you would know whether he said this word out of fear of the weapon or not? He, peace and blessings be upon him, repeated this so many times that I wished in my heart that (I wish) I had embraced Islam just today.