The Spoils of War
فَلَمْ تَقْتُلُوهُمْ وَلَـٰكِنَّ ٱللَّهَ قَتَلَهُمْ ۚ وَمَا رَمَيْتَ إِذْ رَمَيْتَ وَلَـٰكِنَّ ٱللَّهَ رَمَىٰ ۚ وَلِيُبْلِىَ ٱلْمُؤْمِنِينَ مِنْهُ بَلَآءً حَسَنًا ۚ إِنَّ ٱللَّهَ سَمِيعٌ عَلِيمٌ
And you did not kill them, but it was Allah who killed them. And you threw not, [O Muhammad], when you threw, but it was Allah who threw that He might test the believers with a good test. Indeed, Allah is Hearing and Knowing.
Nearby ayahs help place verse 8:17 in sequence and meaning.
يَـٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوٓا۟ إِذَا لَقِيتُمُ ٱلَّذِينَ كَفَرُوا۟ زَحْفًا فَلَا تُوَلُّوهُمُ ٱلْأَدْبَارَ
O you who have believed, when you meet those who disbelieve advancing [for battle], do not turn to them your backs [in flight].
وَمَن يُوَلِّهِمْ يَوْمَئِذٍ دُبُرَهُۥٓ إِلَّا مُتَحَرِّفًا لِّقِتَالٍ أَوْ مُتَحَيِّزًا إِلَىٰ فِئَةٍ فَقَدْ بَآءَ بِغَضَبٍ مِّنَ ٱللَّهِ وَمَأْوَىٰهُ جَهَنَّمُ ۖ وَبِئْسَ ٱلْمَصِيرُ
And whoever turns his back to them on such a day, unless swerving [as a strategy] for war or joining [another] company, has certainly returned with anger [upon him] from Allah, and his refuge is Hell - and wretched is the destination.
ذَٰلِكُمْ وَأَنَّ ٱللَّهَ مُوهِنُ كَيْدِ ٱلْكَـٰفِرِينَ
That [is so], and [also] that Allah will weaken the plot of the disbelievers.
إِن تَسْتَفْتِحُوا۟ فَقَدْ جَآءَكُمُ ٱلْفَتْحُ ۖ وَإِن تَنتَهُوا۟ فَهُوَ خَيْرٌ لَّكُمْ ۖ وَإِن تَعُودُوا۟ نَعُدْ وَلَن تُغْنِىَ عَنكُمْ فِئَتُكُمْ شَيْـًٔا وَلَوْ كَثُرَتْ وَأَنَّ ٱللَّهَ مَعَ ٱلْمُؤْمِنِينَ
If you [disbelievers] seek the victory - the defeat has come to you. And if you desist [from hostilities], it is best for you; but if you return [to war], We will return, and never will you be availed by your [large] company at all, even if it should increase; and [that is] because Allah is with the believers.