كتاب المغازى
64
Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)
(45)
Chapter: The dispatch of Usama bin Zaid to Al-Huraqat
(45)
باب بَعْثُ النَّبِيِّ صلى الله عليه وسلم أُسَامَةَ بْنَ زَيْدٍ إِلَى الْحُرَقَاتِ مِنْ جُهَيْنَةَ

Narrated Usama bin Zaid:

Allah's Messenger (ﷺ) sent us towards Al-Huruqa, and in the morning we attacked them and defeated them. I and an Ansari man followed a man from among them and when we took him over, he said, "La ilaha illal-Lah." On hearing that, the Ansari man stopped, but I killed him by stabbing him with my spear. When we returned, the Prophet (ﷺ) came to know about that and he said, "O Usama! Did you kill him after he had said "La ilaha ilal-Lah?" I said, "But he said so only to save himself." The Prophet (ﷺ) kept on repeating that so often that I wished I had not embraced Islam before that day.

حَدَّثَنِي عَمْرُو بْنُ مُحَمَّدٍ، حَدَّثَنَا هُشَيْمٌ، أَخْبَرَنَا حُصَيْنٌ، أَخْبَرَنَا أَبُو ظَبْيَانَ، قَالَ سَمِعْتُ أُسَامَةَ بْنَ زَيْدٍ ـ رضى الله عنهما ـ يَقُولُ بَعَثَنَا رَسُولُ اللَّهِ صلى الله عليه وسلم إِلَى الْحُرَقَةِ، فَصَبَّحْنَا الْقَوْمَ فَهَزَمْنَاهُمْ وَلَحِقْتُ أَنَا وَرَجُلٌ مِنَ الأَنْصَارِ رَجُلاً مِنْهُمْ، فَلَمَّا غَشِينَاهُ قَالَ لاَ إِلَهَ إِلاَّ اللَّهُ‏.‏ فَكَفَّ الأَنْصَارِيُّ، فَطَعَنْتُهُ بِرُمْحِي حَتَّى قَتَلْتُهُ، فَلَمَّا قَدِمْنَا بَلَغَ النَّبِيَّ صلى الله عليه وسلم فَقَالَ ‏ "‏ يَا أُسَامَةُ أَقَتَلْتَهُ بَعْدَ مَا قَالَ لاَ إِلَهَ إِلاَّ اللَّهُ ‏"‏ قُلْتُ كَانَ مُتَعَوِّذًا‏.‏ فَمَا زَالَ يُكَرِّرُهَا حَتَّى تَمَنَّيْتُ أَنِّي لَمْ أَكُنْ أَسْلَمْتُ قَبْلَ ذَلِكَ الْيَوْمِ‏.‏
Reference : Sahih al-Bukhari 4269
In-book reference : Book 64, Hadith 303
USC-MSA web (English) reference : Vol. 5, Book 59, Hadith 568
  (deprecated numbering scheme)