Surah Fusilat (The Verses Prefectly Explained), Verse 44

وَلَوْ جَعَلْنٰهُ قُرْاٰنًا اَعْجَمِیًّا لَّقَالُوْا لَوْلَا فُصِّلَتْ اٰیٰتُهٗ ءَاَؔعْجَمِیٌّ وَّعَرَبِیٌّ قُلْ هُوَ لِلَّذِیْنَ اٰمَنُوْا هُدًی وَّشِفَآءٌ وَالَّذِیْنَ لَا یُؤْمِنُوْنَ فِیْۤ اٰذَانِهِمْ وَقْرٌ وَّهُوَ عَلَیْهِمْ عَمًی اُولٰٓىِٕكَ یُنَادَوْنَ مِنْ مَّكَانٍ بَعِیْدٍ 

Wa law ja'alnaahu Qur-aanan A'jamiyyal laqaaloo law laa fussilat Aayaatuhoo 'a A'jamiyyunw wa 'Arabiyy; qul huwa lillazeena aamanoo hudanw wa shifaaa'unw wallazeena la yu'minoona feee aazaanihim waqrunw wa huwa 'alaihim 'amaa; ulaaa'ika yunaadawna mim maakaanim ba'eed

“Had We sent this as a Qur'an (in the language) other than Arabic, they would have said: "Why are not its verses explained in detail? What! (a Book) not in Arabic and (a Messenger) an Arab?" Say: "It is a Guide and a Healing to those who believe; and for those who believe not, there is a deafness in their ears, and it is blindness in their (eyes): They are (as it were) being called from a place far distant!"”

Quran 41:44 (Yusuf Ali Translation)