Qur'an 9:127

وَإِذَا مَآ أُنزِلَتْ سُورَةٌ نَّظَرَ بَعْضُهُمْ إِلَىٰ بَعْضٍ هَلْ يَرَىٰكُم مِّنْ أَحَدٍ ثُمَّ ٱنصَرَفُوا۟ ۚ صَرَفَ ٱللَّهُ قُلُوبَهُم بِأَنَّهُمْ قَوْمٌ لَّا يَفْقَهُونَ

And whenever a surah is revealed, they look one at another (as who should say): Doth anybody see you? Then they turn away. Allah turneth away their hearts because they are a folk who understand not.