[Machine] The Messenger of Allah ﷺ sent me on a military expedition with a group of his companions. I competed with a man from the Ansar in hastening towards the enemy. I mounted my horse and as I approached the enemy, the man raised his voice in takbeer (saying Allahu Akbar, meaning "Allah is the Greatest"). I attacked him and killed him. Later, I realized that he only said takbeer to protect himself, but it did not stop me from killing him. When we returned, I went ahead to the Prophet ﷺ and he asked me, "What did you do today, O Usama?" I replied, "I attacked a man who raised his voice in takbeer, thinking he did so to protect himself." The Prophet ﷺ said, "How can you bear to kill him after he said 'Allahu Akbar'? Did you not separate his heart from his body?" I said, "What he said did not deter me." After that day, the Prophet ﷺ kept repeating to me, "I will not fight against a person who says 'Allahu Akbar' more than anything else he says until I meet him."
بَعَثَنِي رَسُولُ اللَّهِ ﷺ فِي سَرِيَّةٍ فِي أُنَاسٍ مِنْ أَصْحَابِهِ فَاسْتَبَقْنَا أَنَا وَرَجُلٌ مِنَ الْأَنْصَارِ إِلَى الْعَدُوِّ فَحَمَلْتُ عَلَى رَجُلٍ فَلَمَّا دَنَوْتُ مِنْهُ كَبَّرَ فَطَعَنْتُهُ فَقَتَلْتُهُ وَرَأَيْتُ أَنَّهُ إِنَّمَا فَعَلَ ذَلِكَ لِيُحْرِزَ دَمَهُ فَلَمَّا رَجَعْنَا سَبَقَنِي إِلَى النَّبِيِّ ﷺ فَقَالَ يَا رَسُولَ اللَّهِ لَا فَارِسَ خَيْرٍ مِنْ فَارِسِكُمْ إِنَّا اسْتَلْحَقْنَا رَجُلًا فَسَبَقَنِي إِلَيْهِ فَكَبَّرَ فَلَمْ يَمْنَعْهُ ذَلِكَ أَنْ قَتَلَهُ فَقَالَ النَّبِيُّ ﷺ «يَا أُسَامَةُ مَا صَنَعْتَ الْيَوْمَ؟» فَقُلْتُ حَمَلْتُ عَلَى رَجُلٍ فَكَبَّرَ فَرَأَيْتُ أَنَّهُ إِنَّمَا فَعَلَ لِيُحْرِزَ دَمَهُ فَقَتَلْتُهُ فَقَالَ «كَيْفَ بَعْدَ اللَّهُ أَكْبَرُ فَهَلَّا شَقَقْتَ عَنْ قَلْبِهِ فَقُلْتُ مَا قَالَ» فَلَمْ يَزَلْ يَقُولُ لِي يَوْمَئِذٍ فَلَا أُقَاتِلُ رَجُلًا يَقُولُ اللَّهُ أَكْبَرُ مِمَّا نَهَانِي عَنْهُ حَتَّى أَلْقَاهُ ﷺ