J. Gresham Machen and the Regulative Principle
[background: Machem lost a professorship at Princeton because he did not support Prohibition]
The Bible did not answer these and various other questions. So, Machen concluded, the church had no business meddling in the politics of Prohibition or any other matter where Scripture did not speak.
Machen's reasoning here was an extension of the Regulative Principle. In the Presbyterian and Reformed tradition this principle has typically been applied to public worship. It teaches that we may only worship God as he has commanded us to worship him in his Word. People who hear this doctrine for the first time often understand it as overly negative and restrictive, as if we have no freedom in worship. Though the Regulative Principle does limit what we may do in worship, just as important is what it teaches about liberty of conscience and the Lordship of Christ. As the Westminster Confession of Faith teaches (20.2), "God alone is Lord of the conscience." To bind the consciences of believers on the teaching of Scripture is to recognize and extend Christ's Lordship. But to do so only on the basis of human wisdom or preference is to usurp his rule.
This principle is what separates Presbyterians from other Protestants. Unlike Lutherans and Anglicans who believe that churches may do whatever God's word allows, Presbyterians and Reformed teach that churches may only do what Scripture commands; hence the name Reformed, "reformed according to the Word."
The Regulative Principle applies not only to worship, but to all aspects of the church's life and witness. Unless the church can find a clear warrant from Scripture for a particular teaching or practice it may not speak or act. Otherwise it runs the risk of binding the consciences of believers and usurping the Lordship of Christ. In this broader sense the Regulative Principle is only a variation on the formal principle of the Reformation, namely, "sola scriptura."