Moreover, it is a well documented fact that the Genevan Presbytery of Calvin's day, in 1536, sought to excommunicate anyone who would not swear an oath to uphold the Reformed doctrine as it was set forth in their Confession of Faith.
T.H.L. Parker writes,
Since the evangelical faith had only recently been preached in the city, and there were still many Romanists, the ministers also urged excommunication on the grounds of failure to confess the faith. The Confession of faith, which all the citizens and inhabitants of Geneva... must promise to keep and to hold had been presented to the Council on 10 November 1536. Let the members of the Council be the first to subscribe and then the citizens, 'in order to recognize those in harmony with the Gospel and those loving rather to be of the kingdom of the pope than of the kingdom of Jesus Christ.' Those who would not subscribe were to be excommunicated (John Calvin: A Biography, p. 63, emphases added).
Moreover, those who would not submit to "Calvin's" close communion were not only proceeded against with negative ecclesiastical sanctions, but they came under negative civil sanctions also.
Dr. Michael Wagner, in Up From Reconstructionism, states,
John Calvin, during the First Reformation, showed that he supported the concept of Covenanted Reformation by requiring all the residents of Geneva to take an oath in support of the Reformation. The 'Register of the Council of 24' of Geneva notes as follows:
12 November 1537. It was reported that yesterday the people who had not yet made their oath to the reformation were asked to do so, street by street; whilst many came, many others did not do so. No one came from the German quarter. It was decided that they should be commanded to leave the city if they did not wish to swear to the reformation(Scribner, Bob and Pamela Johnston. 1993. The Reformation in Germany and Switzerland, Cambridge University Press, p. 138, emphases added).
Now, it should be obvious to those who know the commandments of God that an honest man cannot swear an oath to uphold a confession that he does not believe. To do so, even if the man disagrees with only one point of the confession, is to violate both the third and ninth commandments -- and to play the Jesuit (see the Westminster Larger Catechism on the duties required and the sins forbidden concerning the third and ninth commandments; these can be found as questions and answers 112, 113, 144, and 145). Such false swearing is also, by definition, perjury (I wonder how many perjured officers reside in Presbyterian and Reformed churches today?). To encourage others to so swear is subornation to perjury. These are all serious sins in themselves and all worthy of excommunication and civil penalties -- as the Genevan Reformers rightly taught and practiced.