This emphasis on action, on action to transform a sinful world, has become one of the main characteristics of Calvinism. “By emphasizing the sovereignty of God, Calvin's Institutes leads the reader to believe that no person, king, bishop, or anyone else can demand our ultimate loyalty” (Curtis). Calvin had a high opinion of preaching, but he also encouraged Christians to have a high regard for those who are called to preach. Calvin referred to preachers as “the very mouth of God.” “He said: Those who think that the authority of the Word is weakened by the baseness of the men called to teach it reveal their own ingratitude. For, among the many excellent gifts with which God has adored the human race, it is a singular privilege that he deigns to dedicate to himself the mouths and tongues of men so that his voice may resonate in them..”