Hypocrites and punishment of the grave

وَمِمَّنْ حَوْلَكُم مِّنَ ٱلْأَعْرَابِ مُنَٰفِقُونَ ۖ وَمِنْ أَهْلِ ٱلْمَدِينَةِ ۖ مَرَدُوا۟ عَلَى ٱلنِّفَاقِ لَا تَعْلَمُهُمْ ۖ نَحْنُ نَعْلَمُهُمْ ۚ سَنُعَذِّبُهُم مَّرَّتَيْنِ ثُمَّ يُرَدُّونَ إِلَىٰ عَذَابٍ عَظِيمٍۢ

Certain of the desert Arabs round about you are hypocrites, as well as (desert Arabs) among the Medina folk: they are obstinate in hypocrisy: thou knowest them not: We know them: twice shall We punish them: and in addition shall they be sent to a grievous penalty.