وَإِذَا مَآ أُنزِلَتْ سُورَةٌ نَّظَرَ بَعْضُهُمْ إِلَىٰ بَعْضٍ هَلْ يَرَىٰكُم مِّنْ أَحَدٍ ثُمَّ ٱنصَرَفُوا۟ ۚ صَرَفَ ٱللَّهُ قُلُوبَهُم بِأَنَّهُمْ قَوْمٌ لَّا يَفْقَهُونَ
“Whenever a surah is revealed, they look at one another, [saying,] "Is anyone watching you?" Then they slip away. [It is] Allah [Who] has turned their hearts away because they are a people who do not comprehend.”
Part of the well-established hypocrites-who-stayed-behind-from-Tabuk passage of Surat al-Tawbah.