Surah Yusuf, Verse 2

إِنَّآ أَنزَلۡنَٰهُ قُرۡءَٰنًا عَرَبِيّٗا لَّعَلَّكُمۡ تَعۡقِلُونَ٢

innā anzalnāhu qur'ānan ʿarabiyyan laʿallakum taʿqilūna

Indeed, We have sent it down as an Arabic Qur’ān that you might understand.