Hadith on Jihad: Did you tear open his heart to see his intention?

Usama ibn Zaid said: The Messenger of Allah, peace ad 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!” but I stabbed him. 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’ and you killed him?” I said, “O Messenger of Allah, he only said it fearing of the weapon.” The Prophet said, “Did you tear open his heart to know if he meant it or not?” The Prophet continued to repeat this to me until I had wished I had not embraced Islam until that day.

Source: Ṣaḥīḥ al-Bukhārī 6478, Ṣaḥīḥ Muslim 96

Grade: Muttafaqun Alayhi (authenticity agreed upon) according to Al-Bukhari and 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

6478 صحيح البخاري كتاب الديات باب قول الله تعالى ومن أحياها

96 صحيح مسلم كتاب الإيمان باب تحريم قتل الكافر بعد أن قال لا إله إلا الله