"While traditionally the Quran is considered above the sunna in authority, Al-Shafi'i "forcefully argued" that the sunna stands "on equal footing with the Quran", (according to scholar Daniel Brown) for (as Al-Shafi'i put it) “the command of the Prophet is the command of God.”

In 851 the rationalist Mu`tazila school of thought fell from favor in the Abbasid Caliphate.