Usamah ibn Zayd reported: The Messenger of Allah, peace and blessings be upon him, sent us on an expedition. In the morning we attacked Al-Huraqat of Juhaynah. I caught hold of a man and he said, “There is no God but Allah!” I stabbed him anyway. Then, it occurred to me that I should mention that to the Prophet. The Prophet said, “Did he say ‘there is no God but Allah’ but you killed him?” I said, “O Messenger of Allah, he only said it because he feared the weapon!” The Prophet said, “Did you tear open his heart to know if he meant it or not?” The Prophet continued repeating it to me until I had wished I had not embraced Islam until that day.
Source: Ṣaḥīḥ Muslim 96
Grade: Sahih (authentic) according to Muslim
عَنْ أُسَامَةَ بْنِ زَيْدٍ قَالَ بَعَثَنَا رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فِي سَرِيَّةٍ فَصَبَّحْنَا الْحُرَقَاتِ مِنْ جُهَيْنَةَ فَأَدْرَكْتُ رَجُلًا فَقَالَ لَا إِلَهَ إِلَّا اللَّهُ فَطَعَنْتُهُ فَوَقَعَ فِي نَفْسِي مِنْ ذَلِكَ فَذَكَرْتُهُ لِلنَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَقَالَ لَا إِلَهَ إِلَّا اللَّهُ وَقَتَلْتَهُ قَالَ قُلْتُ يَا رَسُولَ اللَّهِ إِنَّمَا قَالَهَا خَوْفًا مِنْ السِّلَاحِ قَالَ أَفَلَا شَقَقْتَ عَنْ قَلْبِهِ حَتَّى تَعْلَمَ أَقَالَهَا أَمْ لَا فَمَا زَالَ يُكَرِّرُهَا عَلَيَّ حَتَّى تَمَنَّيْتُ أَنِّي أَسْلَمْتُ يَوْمَئِذٍ
96 صحيح مسلم كتاب الإيمان باب تحريم قتل الكافر بعد أن قال لا إله إلا الله
