Mukhtasar Bukhari

´Sayyiduna Usama bin Zaid (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings of Allah be upon him) sent us towards the tribe of Huraqa. In the morning, we attacked that tribe and defeated them. Then I and an Ansari man met a man from the disbelievers. When we surrounded him, he said, "La ilaha illallah" (There is no god but Allah). The Ansari stopped, but I killed him with a spear. When we came to Madinah and the Prophet (peace and blessings of Allah be upon him) heard of this, he said, "Usama! Did you kill him after he said 'La ilaha illallah'?" I submitted that he only said it for protection (not from the heart). The Prophet (peace and blessings of Allah be upon him) kept repeating this, until I wished that I had not accepted Islam before that day (but had accepted it after, so that this sin of mine would have been forgiven).