Mishkat al-Masabih 2 Knowledge كتاب العلم 66

وَعَن الْحسن قَالَ: «الْعِلْمُ عِلْمَانِ فَعِلْمٌ فِي الْقَلْبِ فَذَاكَ الْعلم النافع وَعلم على اللِّسَان فَذَاك حُجَّةُ اللَّهِ عَزَّ وَجَلَّ عَلَى ابْنِ آدَمَ» . رَوَاهُ الدَّارمِيّ

Al-Hasan said that knowledge is of two kinds: knowledge in the heart, which is the beneficial type; and knowledge on the tongue, which is God’s allegation against a human being.” Darimi transmitted it.