"But if you do wrong, be afraid, for he does not bear the sword in vain. For he is the servant of God, an avenger who carries out God's wrath on the wrongdoer."
Faithful discipleship has ramifications not only for our relationship to the church but also for our relationship to the state, as Paul explains in Romans 13:1-7. Freedom in Christ does not mean freedom from the need to obey the government; rather, freedom in Christ entails submission to the governing authorities because they are the Lord's appointed means of maintaining order in society (vv. 1-2). As a general rule, earthly governments punish wrongdoing and do not threaten those who do good, so in most cases, Christians obey God when they obey the secular authorities (vv. 3-4a).
Paul expands upon the role of governments in today's passage, telling us that the government's vocation is to carry the sword and execute God's wrath on the wrongdoer (v. 4b). Among other things, this tells us that there is a division of labor between the state and the church in the new covenant era. Only the state has the right to take up arms in the punishment of the wicked. The church deals with the impenitent in its midst through the practice of church discipline, culminating in excommunication if necessary (Matt. 18:15-20; 1 Cor. 5). The church is not to exercise the punishment of physical force against heretics and recalcitrant sinners. On the other hand, the state's job is to use physical force against those who break the law. Christians may be called to work for the state as judges, police officers, lawmakers, soldiers, and so forth, and in that capacity they may bear the sword against wrongdoers. But the church herself has no right to bear the sword against her enemies.
Romans 13:4b also justifies the right use of capital punishment. Although many Christians have believed that the state may not execute people for offences such as murder, the Bible does not substantiate their position. Those who commit what we would refer to as first-degree murder must be executed, because murder is an attempt to destroy God's image (Gen. 9:5- 6). This heinous sin can be forgiven by God, but that does not mean we set aside its earthly consequences. Moreover, while we should do all that we can to make sure mistakes are not made in carrying out capital punishment, the fact that errors have occurred does not mean abolishing the death penalty is the answer. John Calvin comments, "If the Lord, by arming the magistrate, has also committed to him the use of the sword, whenever he visits the guilty with death, by executing God's vengeance, he obeys his commands. Contend then do they with God who think it unlawful to shed the blood of wicked men."
Coram Deo
There is a division of labor between the state and the church. The state punishes evildoers with the sword, and the church preaches the gospel. The state may not do the church's job, and the church may not do the state's job. However, that does not mean the church may not speak to the state. In fact, the church is to be the conscience of the state, calling it to do its job of protecting human life and punishing criminals.