Surah Fussilat, Verse 44
وَلَوْ جَعَلْنَٰهُ قُرْءَانًا أَعْجَمِيًّۭا لَّقَالُوا۟ لَوْلَا فُصِّلَتْ ءَايَٰتُهُۥٓ ۖ ءَا۬عْجَمِىٌّۭ وَعَرَبِىٌّۭ ۗ قُلْ هُوَ لِلَّذِينَ ءَامَنُوا۟ هُدًۭى وَشِفَآءٌۭ ۖ وَٱلَّذِينَ لَا يُؤْمِنُونَ فِىٓ ءَاذَانِهِمْ وَقْرٌۭ وَهُوَ عَلَيْهِمْ عَمًى ۚ أُو۟لَٰٓئِكَ يُنَادَوْنَ مِن مَّكَانٍۭ بَعِيدٍۢ
Translation — Sahih International
And if We had made it a non-Arabic Qur'an, they would have said, "Why are its verses not explained in detail [in our language]? Is it a foreign [recitation] and an Arab [messenger]?" Say, "It is, for those who believe, a guidance and cure." And those who do not believe - in their ears is deafness, and it is upon them blindness. Those are being called from a distant place.
Source
Kur'an-ı Kerim, Fussilet Suresi 41:44
https://kuran.diyanet.gov.tr/mushaf/kuran-meal-2/41-suresi-44-ayet