English translation
6872. Narrated Usāma bin Zaid bin Hārītha رَضِيَ اللَّهُ عَنْهُمَا: Allāh's Messenger ﷺ sent us (to fight) against Al-Huraqa (one of the subtribes) of Juhaina. We reached those people in the morning and defeated them. A man from the Anṣār and I chased one of their men and when we attacked him, he said, "Lā ilāha illallāh" (none has the right to be worshipped but Allāh). The Anṣārī refrained from killing him but I stabbed him with my spear till I killed him. When we reached (Al-Madīna), this news reached the Prophet ﷺ. He said to me, "O Usāma! You killed him after he had said, 'Lā ilāha illallāh?' " I said, "O Allāh's Messenger! He said so in order to save himself." The Prophet said, "You killed him after he had said, 'Lā ilāha illallāh' (None has the right to be worshipped but Allāh)." The Prophet ﷺ kept on repeating that statement till I wished I had not been a Muslim before that day.