اٰل عمران — Ali 'Imran Ayat 166

وَمَآ اَصَابَكُمْ يَوْمَ الْتَقَى الْجَمْعٰنِ فَبِاِذْنِ اللّٰهِ وَلِيَعْلَمَ الْمُؤْمِنِيْنَۙ

Wa mā aṣābakum yaumal-taqal-jam‘āni fa bi'iżnillāhi wa liya‘lamal-mu'minīn(a).

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