سورة Aal-Imran 3:166

وَمَآ أَصَـٰبَكُمْ يَوْمَ ٱلْتَقَى ٱلْجَمْعَانِ فَبِإِذْنِ ٱللَّهِ وَلِيَعْلَمَ ٱلْمُؤْمِنِينَ ١٦٦

So what you suffered on the day the two armies met was by Allah’s Will, so that He might distinguish the ˹true˺ believers