وَلَقَدْ نَعْلَمُ أَنَّهُمْ يَقُولُونَ إِنَّمَا يُعَلِّمُهُۥ بَشَرٌ ۗ لِّسَانُ ٱلَّذِى يُلْحِدُونَ إِلَيْهِ أَعْجَمِىٌّ وَهَـٰذَا لِسَانٌ عَرَبِىٌّ مُّبِينٌ
Wa laqad na'lamu annahum yaqooloona innamaa yu'allimuhoo bashar; lisaanul lazee yulhidoona ilaihi a'ja miyyunw wa haaza lisaanun 'Arabiyyum mubeen
We know very well that they say, ‘It is a man who teaches him,’ but the language of the person they allude to is foreign, while this revelation is in clear Arabic.
And we know well that they say, "It is only a man who teaches him." The tongue of the one they hint at is foreign, while this is clear Arabic speech.