Sayyiduna Usama bin Zaid (may Allah be pleased with him) narrated that the Messenger of Allah (peace and blessings be upon him) sent us towards the tribe of Huraqa. We attacked them in the morning and defeated them. Then I and another Ansari companion confronted a man from this tribe (Mirdas bin Amr). When we overpowered him, he began to say "La ilaha illallah" (There is no god but Allah). The Ansari immediately stopped, but I killed him with my spear. When we returned, the Prophet (peace and blessings be upon him) was informed of this. He asked, "Usama, did you kill him even after he said 'La ilaha illallah'?" I replied, "He only said it to save himself (he did not say it from his heart)." The Prophet (peace and blessings be upon him) kept repeating, "Did you kill him even after he said 'La ilaha illallah'?" until I wished that I had not accepted Islam before that day.