Luther and Calvin on Secular Authority (Cambridge Texts in the History of Political Thought) (Paperback)
This book deserves a couple of reads. Serious theologians, pastors, political parishioners can all benefit from a careful reading of this book. Today with the religious right, and secularists battling it out in every political campaign, a culture war doing the culture more harm than good from both sides, this book needs to be read more.
For the most part, aside from some commentary you have Luther's writings and Calvin's writings on both sides. Tricky is to see the subtle difference that becomes profound in practice. Luther says that there are two authorities to which all CHRISTIANS are subject. Calvin starts his treatise saying that all men are subject to both these same authorities. This makes a profound difference in what the church is and what the state is. For Luther the church is about the gospel proclaiming the forgiveness of sins, and the only people that are subject to whatever authority it has are Christians who have been won for Christ by the work of the Holy Spirit. They willfully follow the churches teachings concerning morality, and subject themselves to the forgiveness of sins. The two authorities are the church and state. Christians don't need the state to tell them to do good, in so far as they are Christian, but saint and sinner, as they are the state will need to curb the activity even of Christians at times for the good of society.
However, the state is about enforcing laws and keeping peace. To this end all people need be subject to it. The state can't afford to forgive sins, or confuse its role with that of the church. To the state has been entrusted the sword, and it isn't for good looks.
Calvin though would confuse this by making all people subject to both the church and the state, there may as well be only one authority then. And sadly as Calvin's Geneva showed this becomes the case. Rather than being about the forgiveness of sins, the church becomes a persecutor, another arm of the state enforcing man made laws in the name of Christ.
This book does much to show the differences between the two men. Luther was not a Calvinist.