What we believe about God-- who He is and what He is like-- will determine our behavior. If we believe God is sovereign, holy, and involved in creation, we will live obedient, surrendered lives. If we believe God is not sovereign, or he is holy is only some areas, or if he is not really involved in creation, we will live pretty much how we want to live.
Our beliefs always determine our behavior. But our behavior reveals what we really believe.