John Calvin on Romans 13:4

4. For he is God’s minister for good, etc. Magistrates may hence learn what their vocation is, for they are not to rule for their own interest, but for the public good; nor are they endued with unbridled power, but what is restricted to the wellbeing of their subjects; in short, they are responsible to God and to men in the exercise of their power. For as they are deputed by God and do his business, they must give an account to him: and then the ministration which God has committed to them has a regard to the subjects, they are therefore debtors also to them. And private men are reminded, that it is through the divine goodness that they are defended by the sword of princes against injuries done by the wicked.

For they bear not the sword in vain, etc. It is another part of the office of magistrates, that they ought forcibly to repress the waywardness of evil men, who do not willingly suffer themselves to be governed by laws, and to inflict such punishment on their offenses as God’s judgment requires; for he expressly declares, that they are armed with the sword, not for an empty show, but that they may smite evil-doers.

And then he says, An avenger, to execute wrath, Vindex in iram, ἔκδικος εἰς ὀργὴν; “a revenger to execute wrath,” Com. Ver., Doddridge; “a revenger for wrath,” Hammond. Wrath is here taken to mean punishment, by Luther, Beza, Grotius, Mede, etc. see Romans 2:5; Romans 3:5; Romans 4:15. The phrase then might be rendered, “condemning to punishment the doer of evil.” There is a contrast between “for wrath” and “for good” at the beginning of the verse. — Ed. etc. This is the same as if it had been said, that he is an executioner of God’s wrath; and this he shows himself to be by having the sword, which the Lord has delivered into his hand. This is a remarkable passage for the purpose of proving the right of the sword; for 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.

Romans 13:5-7

5. Wherefore ye must needs be subject, not only for wrath, but also for conscience sake.

5. Itaque necesse est subjici, non modo propter iram, sed etiam propter conscientiam.

6. For, for this cause pay ye tribute also: for they are God’s ministers, attending continually upon this very thing.

6. Propterea enim tributa quoque solutis; ministri “Ministri,” λειτουργοὶ, administrators, functionaries, the performers of public service, or public ministers, according to Macknight. Rulers were called before, in Romans 13:4, διάκονοι, servants, deacons, ministers. The same titles are given to them as to the Apostles and ministers of the gospel, and even to Christ himself: and they are said to be the ministers and functionaries of God, being so in civil matters, as those are in spiritual things who preach the gospel. — Ed. enim Dei sunt, in hoc incumbentes.

7. Render therefore to all their dues: tribute to whom tribute is due; custom to whom custom; fear to whom fear; honour to whom honour.

7. Reddite ergo omnibus quod debetur; cui tributum, tributum; cui vectigal, vectigal; cui timorem, timorem; cui honorem, honorem.