Around the 1530s, numerous clerics faced the difficult choice either to mobilize themselves for the Reformation, or to work to oppose its principles. This article investigates the situation in the Old Swiss Confederacy, where priests, monks, and preachers who had embraced the new faith had to contend with magistrates who saw themselves as the guarantors of salvation, and to convince the communes where the choice of religion was decided on in a referendum. By considering the specific political contexts, the social conditions of the clerics’ engagement, and the increasingly important place knowledge of the Word of God took on—over ordination—for a legitimated gospel proclamation, this article will demonstrate that it was not by their own virtue that the Reformed doctrines managed to impose themselves, but by the efforts of men capable, by reason of their social properties and position, of carrying these ideas. This approach opens up a perspective on the logic behind the choices that were at once individual and reflective of collective aspirations, and to understand the role of professional habits and the local balance of power in the specific context of the Old Swiss Confederacy.