Sahih Bukhari Volume 6, Book 65, Hadith 4598

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يَزِيدَ الْمُقْرِئُ، حَدَّثَنَا حَيْوَةُ، وَغَيْرُهُ، قَالاَ حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ الرَّحْمَنِ أَبُو الأَسْوَدِ، قَالَ قُطِعَ عَلَى أَهْلِ الْمَدِينَةِ بَعْثٌ فَاكْتُتِبْتُ فِيهِ، فَلَقِيتُ عِكْرِمَةَ مَوْلَى ابْنِ عَبَّاسٍ فَأَخْبَرْتُهُ، فَنَهَانِي عَنْ ذَلِكَ أَشَدَّ النَّهْىِ، ثُمَّ قَالَ أَخْبَرَنِي ابْنُ عَبَّاسٍ أَنَّ نَاسًا مِنَ الْمُسْلِمِينَ كَانُوا مَعَ الْمُشْرِكِينَ يُكَثِّرُونَ سَوَادَ الْمُشْرِكِينَ عَلَى رَسُولِ اللَّهِ صلى الله عليه وسلم يَأْتِي السَّهْمُ فَيُرْمَى بِهِ، فَيُصِيبُ أَحَدَهُمْ فَيَقْتُلُهُ أَوْ يُضْرَبُ فَيُقْتَلُ، فَأَنْزَلَ اللَّهُ ‏{‏إِنَّ الَّذِينَ تَوَفَّاهُمُ الْمَلاَئِكَةُ ظَالِمِي أَنْفُسِهِمْ‏}‏ الآيَةَ‏.‏ رَوَاهُ اللَّيْثُ عَنْ أَبِي الأَسْوَدِ‏.‏

Narrated By Muhammad bin Abdur-Rahman Abu Al-Aswad : The people of Medina were forced to prepare an army (to fight against the people of Sham during the caliphate of 'Abdullah bin Az-Zubair at Mecca), and I was enlisted in it; Then I met 'Ikrima, the freed slave of Ibn 'Abbas, and informed him (about it), and he forbade me strongly to do so (i.e. to enlist in that army), and then said, "Ibn 'Abbas informed me that some Muslim people were with the pagans, increasing the number of the pagans against Allah's Apostle. An arrow used to be shot which would hit one of them (the Muslims in the company of the pagans) and kill him, or he would be struck and killed (with a sword)." Then Allah revealed: "Verily! as for those whom the angels take (in death) while they are wronging themselves (by staying among the disbelievers)" (4.97)