The Shi’ahs say: Man is obliged by his reason to know God, and to obey His commands. The Sunnis say: Reason has nothing to do with anything. Of course, it is necessary to believe in Allah, but not on account of reason. It is necessary because Allah has ordered us to know Him. According to the Shiite view, this type of proof creates a vicious circle. Believe in God. Why? Because God has ordered it. But we do not know who is God. Why should we obey Him?
The Shi’ahs say: God cannot give us a command beyond our strength, because it is wrong rationally. The Sunnis do not agree with it.