This emphasis on doing, on acting to transform a sinful world, became 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 command our utmost loyalty” (Curtis). Calvin had a high view of preaching, but he also encouraged Christians to have a high regard for those who are called to preach. Calvin alluded to preachers as the “very mouth of God.” “He said: Those who think that the authority of the Word is weakened by the vileness of the men called to teach it reveal their own ingratitude. In fact, among the many excellent gifts with which God has adored the human race, it is a singular privilege that he deigns to consecrate the mouths and tongues of men to himself so that his voice may resound in them..”