Gospel Threatenings
Not only the letters to the seven churches, but also passages in Paul’s epistles, prove this point. For instance, Paul warns believers that “if you live according to the flesh you will die, but if by the Spirit you put to death the deeds of the body, you will live” (Rom. 8:13). This is not a “law threatening,” but rather a “gospel threatening.” In the WCF, believers are those who yield obedience to God’s commands, tremble at his threatenings, and embrace his promises (14.2). God’s commands, threatenings, and promises for believers are all derived from the gospel, largely understood. In fact, the most severe warnings in the Scriptures are made to professing Christians, and for that reason they are gospel warnings (see Heb. 10:26–31).
Mark Jones, Antinomianism: Reformed Theology's Unwelcome Guest? (Phillipsburgs, New Jersey: P&R Publishing, 2013), 49-50