Mishkat al-Masabih 2 Knowledge كتاب العلم 36

وَعَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: ” الْعِلْمُ ثَلَاثَةٌ: آيَةٌ مُحْكَمَةٌ أَوْ سُنَّةٌ قَائِمَةٌ أَوْ فَرِيضَةٌ عَادِلَةٌ وَمَا كَانَ سِوَى ذَلِكَ فَهُوَ فضل ” . رَوَاهُ أَبُو دَاوُد وَابْن مَاجَه

‘Abdallah b. ‘Amr reported God’s messenger as saying, “Knowledge has three categories: a precise verse, or an established sunna , or a firm obligatory duty. Anything else is an extra.” Abu Dawud and Ibn Majah transmitted it.