In an Advent sermon from 1532 preached at the stadtkirche, Luther noted the difference between the Lord Christ’s kingdom and that of the lord Caesar. Luther said it in Latin: finis politiae est pax mundi; finis ecclesiae est pax aeterna. Here’s his explanation:
“The end purpose of the government is temporal peace, while the ultimate end of the church is not peace and comfort on earth, nice homes, wealth, power, and honor, but everlasting peace. Caesar does not care whether I die a blessed death and come to everlasting life, nor can he be of help against death, but must himself die just like me. Death comes to him as [it does] to the lowly beggar. Caesar’s jurisdiction pertains to this temporal, transitory life; but where this temporal life ceases, there the rule of the Christian church intervenes. Let this be the goal and purpose for which the Christian realm strives and aims: to proclaim the treasure for troubled and anguished consciences which Christ has earned for and committed to his church, namely, the forgiveness of sins and everlasting peace.”
Quotes taken from page 103 of volume 5 of the Baker set of Luther’s sermons. For more info on Luther’s two kingdoms, along with the Lutheran confessions be sure to check out this book - (just released).
Earlier, I noted Watson and Bavinck’s notes on the kingship of Christ, as well as Luther’s. It was pretty “standard speak” in the Reformation and post-Reformation schools to talk about the reign of Christ (regnum Christi) in a threefold way. Brakel (and the aforementioned Reformers) used these terms: Christ’s kingly office is threefold: 1) “He rules over the kingdom of power, to which all creatures belong,” 2) he rules “as Mediator over the kingdom of grace upon earth,” and 3) he rules “over the kingdom of glory in heaven.” Of course the latter two are also what the Reformers referred to as the church militant and the church triumphant – one church existing in the “already/not yet” tension. Again by way of reminder, Watson, Bavinck, Luther, and many others used these exact terms, including Ursinus (yes, you can think these thoughts when reading the Heidelberg). See Muller’s fine Dictionary of Latin and Greek Theological Terms s.v. regnum Christi for more helpful info.
After making the threefold distinction, Brakel goes on to give some verses supporting these distinctions. Interestingly, he also here has a subsection entitled, “The Separation Between Church and State.” Here, not surprisingly, he sounds like Turretin. Brakel writes this:
“The one is heavenly and the other earthly. The one pertains to souls and the other to the body. The one is characterized by servanthood…the other is characterized by authority and dominion. The one is not to meddle in the affairs of the other. …Thus must everyone function within his own sphere. The church is not to rule over the state and the state may not rule over the church, but each must limit itself to its own domain” (The Christian’s Reasonable Service, I.561-566)
This is fascinating, especially in Holland, where the “state church” was the order of Brakel’s day (c. 1700). Brakel notes that governments should allow the church to preach the gospel so that the members of the church can submit to the government, but he also says the government cannot lord anything over the church as church, only her individual members as they must obey the magistrate. It would be a fascinating study to draw some lines (political and theological) from Luther to Ursinus to Turretin to Brakel to Bavinck, throwing Watson in the mix as well.