Surah An-Nahl, Verse 103
وَلَقَدْ نَعْلَمُ أَنَّهُمْ يَقُولُونَ إِنَّمَا يُعَلِّمُهُۥ بَشَرٌۭ ۗ لِّسَانُ ٱلَّذِى يُلْحِدُونَ إِلَيْهِ أَعْجَمِىٌّۭ وَهَٰذَا لِسَانٌ عَرَبِىٌّۭ مُّبِينٌ
Translation — Sahih International
And We certainly know that they say, "It is only a human being who teaches the Prophet." The tongue of the one they refer to is foreign, and this Qur'an is [in] a clear Arabic language.
Source
Kur'an-ı Kerim, Nahl Suresi 16:103
https://kuran.diyanet.gov.tr/mushaf/kuran-meal-2/16-suresi-103-ayet