قَوْلُهُ تَعَالَى: {فَمَا لَكُمْ فِي الْمُنَافِقِينَ فِئَتَيْنِ وَاللهُ أَرْكَسَهُمْ} [النساء: 88]
Some of the companions of the Prophet ﷺ returned from the battle of Uhud (i.e. refused to fight) whereupon the Muslims got divided into two parties; one of them was in favor of their execution and the other was not in favour of it. So there ware revealed: "Then what is the matter with you that you are divided into two parties about the hypocrites?" (4.88). Then the Prophet ﷺ said "It (i.e. Medina) is a Taybah (good), it expels impurities as the fire expels the impurities of silver." (Using translation from Bukhārī 4589)
فِي هَذِهِ الْآيَةِ فَمَا لَكُمْ فِي الْمُنَافِقِينَ فِئَتَيْنِ وَاللهُ أَرْكَسَهُمْ بِمَا كَسَبُوا قَالَ رَجَعَ نَاسٌ مِنْ أَصْحَابِ رَسُولِ اللهِ ﷺ مِنْ أُحُدٍ فَكَانَ النَّاسُ فِيهِمْ فِرْقَتَيْنِ فَرِيقٌ مِنْهُمْ يَقُولُ اقْتُلْهُمْ وَفَرِيقٌ يَقُولُ لَا فَنَزَلَتِ الْآيَةُ فَمَا لَكُمْ فِي الْمُنَافِقِينَ فِئَتَيْنِ وَقَالَ إِنَّهَا تَنْفِي الْخَبَثَ كَمَا تَنْفِي النَّارُ خَبَثَ الْفِضَّةِ