وَمَاۤ اَصَابَكُمۡ يَوۡمَ الۡتَقَى الۡجَمۡعٰنِ فَبِاِذۡنِ اللّٰهِ وَلِيَعۡلَمَ الۡمُؤۡمِنِيۡنَۙ
And the agony that hurt you on the day when the two armies clashed with each other came about (only) by Allah’s Command And (this happened) so that Allah establishes the identity of the believers,