[O Prophet, fight against the disbelievers and the hypocrites and be harsh upon them] Al-Hasan's explanation: Fight the hypocrites with the sword, and be harsh upon the hypocrites by [enforcing] the legal penalties (hudud).
Al-Hasan said: Most of those upon whom the legal penalties were inflicted in those days were the hypocrites.
﴿يَا أَيهَا النَّبِيُّ جَاهِدِ الْكُفَّارَ وَالْمُنَافِقِينَ وَاغْلُظْ عَلَيْهِم﴾ تَفْسِيرُ الْحَسَنِ: جَاهِدِ الْمُنَافِقِينَ بِالسَّيْفِ، وَاغْلُظْ عَلَى الْمُنَافِقِينَ بِالْحُدُودِ.
قَالَ الْحَسَنُ: كَانَ أَكْثَرُ مَنْ يُصِيبُ الْحُدُود يومئذٍ المُنَافِقُونَ.