Turn to God and to His prophet for guidance whenever you feel uncertain as to what you have to do. There is the commandment of God delivered to those people who He wishes to guide aright:
“O people of the Faith! Obey God and obey His prophet and those from among you who hold authority over you. And refer to God and His prophet whenever there is difference of opinion among you.” (4:59)
To turn to God is in reality to consult the Book of God; and to turn to the prophet is t follow his universally accepted traditions.
Imam ‘Ali’s famous letter of advice while Caliph, to the Governor of Egypt, Malik al-Ashtar