3:166
وَمَآ أَصَـٰبَكُمْ يَوْمَ ٱلْتَقَى ٱلْجَمْعَانِ فَبِإِذْنِ ٱللَّهِ وَلِيَعْلَمَ ٱلْمُؤْمِنِينَ١٦٦
And what struck you on the day the two armies met [at Uḥud] was by permission of Allāh that He might make evident the [true] believers
— Saheeh International