وَمَا٘ اَصَابَكُمۡ يَوۡمَ الۡتَقَي الۡجَمۡعٰنِ فَبِاِذۡنِ اللّٰهِ وَلِيَعۡلَمَ الۡمُؤۡمِنِيۡنَۙ‏

And what struck you on the day the two armies met was by permission of Allah that He might make evident the [true] believers