Salamah bin Al Akwa’ said “On the day of the battle of the Khaibar, my brother fought desperately. But his sword fell back on him and killed him. The Companions of the Apostle of Allaah ﷺ talked about him and doubted it (his martyrdom) saying “A man who died with his own weapon”. The Apostle of Allaah ﷺ said “he died as a warrior striving in the path of Allaah. Ibn Shihab said “I asked the son of Salamah bin Al Akwa’.” He narrated to me on the authority of his father similar to that except that he said “The Apostle of Allaah ﷺ said “They told a lie, he died as a warrior striving in the path of Allaah. There is a double reward for him.”” (Using translation from Abū Dāʾūd 2538)   

لَمَّا كَانَ يَوْمُ خَيْبَرَ قَاتَلَ أَخِي قِتَالًا شَدِيدًا فَارْتَدَّ عَلَيْهِ سَيْفُهُ فَقَتَلَهُ فَقَالَ أَصْحَابُ رَسُولِ اللهِ ﷺ فِي ذَلِكَ وَشَكُّوا فِيهِ رَجُلٌ مَاتَ بِسِلَاحِهِ فَقَالَ رَسُولُ اللهِ ﷺ مَاتَ جَاهِدًا مُجَاهِدًا قَالَ ابْنُ شِهَابٍ ثُمَّ سَأَلْتُ ابْنًا لِسَلَمَةَ بْنِ الْأَكْوَعِ فَحَدَّثَنِي عَنْ أَبِيهِ بِمِثْلِ ذَلِكَ غَيْرَ أَنَّهُ قَالَ فَقَالَ رَسُولُ اللهِ ﷺ كَذَبُوا مَاتَ جَاهِدًا مُجَاهِدًا فَلَهُ أَجْرُهُ مَرَّتَيْنِ