يَحْذَرُ الْمُنَافِقُونَ أَن تُنَزَّلَ عَلَيْهِمْ سُورَةٌ تُنَبِّئُهُم بِمَا فِي قُلُوبِهِمْ ۚ قُلِ اسْتَهْزِئُوا إِنَّ اللَّهَ مُخْرِجٌ مَّا تَحْذَرُونَ
“The munafiqun are terrified that Allah will reveal something that will expose what is in their hearts.”
This is the specific asbab al-nuzul the post narrates: the ayah exposing the hypocrites' "joking" excuse was revealed as the accused ran up to make it.