Allah the Exalted said: «ومن لم يحكم بما أنزل الله فأولئك هم الظالمون» Those who do not judge according to what Allah has revealed, they are the wrongdoers. And the Prophet (peace and blessings of Allah be upon him) praised the scholar who judges according to knowledge (Qur'an and Hadith), teaches people the Qur'an and Hadith, and does not say anything from himself. In this matter, it is also mentioned that the caliphs consulted the people of knowledge.

Narrated `Abdullah: Allah's Apostle said, "Do not wish to be like anybody except in two cases: The case of a man whom Allah has given wealth and he spends it in the right way, and that of a man whom Allah has given religious wisdom (i.e., Qur'an and Sunna) and he gives his verdicts according to it and teaches it." (to others i.e., religious knowledge of Qur'an and Sunna (Prophet's Traditions)). "