Much has been written in the past on the subject of John Calvin and his views on the relationship of the Civil Magistrate and the Church. Many have attempted to present a view of Calvin that would be opposed to the use of the law and the duties of the Christian Magistrate as presented in the Westminster Confession. However, I believe much of that is due to the unfortunate lack of availability of Calvin's most developed theology of the law and civil magistrate being found in his sermons on Deuteronomy, preached very late in his life.
As you will find from the numerous selections of Calvin's writings collected below, the consistent teaching of his life's voluminous work brings us to the inescapable conclusion that he believed, as the Westminster Assembly did, that Scripture teaches both that Church and State are under the authority of God and that they are governed separately but with God-ordained responsibilities to each other. And further, in addition to the abiding nature of the ten commandments as moral laws, that the Christian civil magistrate has a duty to promote true religion, protect the church and to punish first table offenses (those who violate the first through fourth commandments), and not only those of the second table.
The Magistrate does not have the right to interfere in the governance of the Church:
And hence all that these holy men sought by this exception was, to prevent irreligious princes from impeding the Church in the discharge of her duty, by their tyrannical caprice and violence. They did not disapprove when princes interposed their authority in ecclesiastical affairs, provided this was done to preserve, not to disturb, the order of the Church, to establish, not to destroy discipline. For, seeing the Church has not, and ought not to wish to have, the power of compulsion (I speak of civil coercion), it is the part of pious kings and princes to maintain religion by laws, edicts, and sentences. In this way, when the emperor Maurice had commanded certain bishops to receive their neighbouring colleagues, who had been expelled by the Barbarians, Gregory confirms the order, and exhorts them to obey. He himself, when admonished by the same emperor to return to a good understanding with John, Bishop of Constantinople, endeavours to show that he is not to be blamed; but so far from boasting of immunity from the secular forum, rather promises to comply as far as conscience would permit: he at the same time says, that Maurice had acted as became a religious prince, in giving these commands to priests.
Calvin’s Comments on Isaiah 49:23, and the duties of magistrates under the gospel:
23. And kings shall be thy nursing fathers.
After having spoken of the obedience of the Gentiles, he shews that this relates not to the common people only, but to “kings” also. He compares “kings” to hired men who bring up the children of others, and “queens” to “nurses,” who give out their labor for hire. Why so? Because “kings” and “queens” shall supply everything that is necessary for nourishing the offspring of the Church. Having formerly driven out Christ from their dominions, they shall henceforth acknowledge him to be the supreme King: and shall render to him all honor, obedience, and worship. This took place when the Lord revealed himself to the whole world by the Gospel; for mighty kings and princes not only submitted to the yoke of Christ, but likewise contributed their riches to raise up and maintain the Church of Christ, so as to be her guardians and defenders.
Hence it ought to be observed that something remarkable is here demanded from princes, besides an ordinary profession of faith; for the Lord has bestowed on them authority and power to defend the Church and to promote the glory of God. This is indeed the duty of all; but kings, in proportion as their power is greater, ought to devote themselves to it more earnestly, and to labor in it more diligently. And this is the reason why David expressly addresses and exhorts them to “be wise, and serve the Lord, and kiss his Son.” (Psalm 2:10-12.)
This shews how mad are the dreams of those who assert that kings cannot be Christians without laying aside that office; for those things were accomplished under Christ, when kings, who had been converted to God by the preaching of the Gospel, obtained this highest pinnacle of rank, which surpasses dominion and principality of every sort, to be “nursing-fathers” and guardians of the Church. The Papists have no other idea of kings being “nursing-fathers” of the Church than that they have left to their priests and monks very large revenues, rich possessions and prebends, on which they might fatten, like hogs in a sty. But that “nursing” aims at an object quite different from filling up those insatiable gulls. Nothing is said here about enriching the houses of those who, under false pretences, hold themselves out to be ministers of the Church, (which was nothing else than to corrupt the Church of God and to destroy it by deadly poison,) but about removing superstitions and putting an end to all wicked idolatry, about advancing the kingdom of Christ and maintaining purity of doctrine, about purging scandals and cleansing from the filth that corrupts piety and impairs the lustre of the Divine majesty.
Undoubtedly, while kings bestow careful attention on these things, they at the same time supply the pastors and ministers of the Word with all that is necessary for food and maintenance, provide for the poor and guard the Church against the disgrace of pauperism; erect schools, and appoint salaries for the teachers and board for the students; build poor-houses and hospitals, and make every other arrangement that belongs to the protection and defense of the Church. But those unnecessary and extravagant expenses for Anniversaries and Masses, for golden vessels and costly robes, which swell the pride and insolence of papists, serve only to uphold pomp and ambition, and corrupt the pure and simple “nursing” of the Church, and even choke and extinguish the seed of God, by which alone the Church lives. When we see that matters are now very different, and that “kings” are not the “nursing-fathers,” but the executioners of the Church; when, in consequence of taking away the doctrine of piety and banishing its true ministers, idle bellies, insatiable whirlpools, and messengers of Satan, are fattened, (for such are the persons to whom the princes cheerfully distribute their wealth, that is, the moisture and blood which they have sucked out of the people;) when even princes otherwise godly have less strength and firmness for defending the Word and upholding the Church; let us acknowledge that this is the reward due to our sins, and let us confess that we do not deserve to have good “nursing-fathers.” But yet, after this frightfully ruinous condition, we ought to hope for a restoration of the Church, and such a conversion of kings that they shall shew themselves to be “nursing-fathers” and protectors of believers, and shall bravely defend the doctrine of the Word.And shall lick the dust of thy feet.
Here the Prophet means nothing else than the adoration by which princes bow down before God, and the obedience which they render to his Word in the Church. What we have already said must be carefully observed, that, when we speak of rendering honor to the Church, she must never be separated from the Head; for this honor and worship belongs to Christ, and, when it is bestowed on the Church, it still continues to belong undivided to him alone. By the obedience of piety kings do not profess submission, so as to bear the yoke of men, but to yield to the doctrine of Christ. Whosoever therefore rejects the ministry of the Church, and refuses to bear the yoke which God wishes to lay with his own hand on all his people, can neither have any fellowship with Christ nor be a child of God.For they shall not be ashamed.
I consider ‘sr (asher) to be a conjunction signifying For;  and the clause to which it belongs is closely connected with what goes before, and has been improperly disjoined from it by some commentators. By this argument he proves that it is highly proper for princes to submit cheerfully to the government of God, and not hesitate to humble themselves before the Church; because God will not suffer those who hope in him to “be ashamed.” As if he had said, “This is a pleasant and delightful submission.”
Calvin affirms the same again in Institutes 21.5:
Those who are desirous to introduce anarchy object that, though anciently kings and judges presided over a rude people, yet that, in the present day, that servile mode of governing does not at all accord with the perfection which Christ brought with his gospel. Herein they betray not only their ignorance, but their devilish pride, arrogating to themselves a perfection of which not even a hundredth part is seen in them. But be they what they may, the refutation is easy. For when David says, “Be wise now therefore, O ye kings: be instructed, ye judges of the earth;” “Kiss the Son, lest he be angry” (Psalm 2:10, 12), he does not order them to lay aside their authority and return to private life, but to make the power with which they are invested subject to Christ, that he may rule over all. In like manner, when Isaiah predicts of the Church, “Kings shall be thy nursing-fathers, and their queens thy nursing-mothers” (Isaiah 49:23), he does not bid them abdicate their authority; he rather gives them the honourable appellation of patrons of the pious worshippers of God; for the prophecy refers to the advent of Christ. I intentionally omit very many passages which occur throughout Scripture, and especially in the Psalms, in which the due authority of all rulers is asserted. The most celebrated passage of all is that in which Paul, admonishing Timothy, that prayers are to be offered up in the public assembly for kings, subjoins the reason, “that we may lead a quiet and peaceable life in all godliness and honesty” (1 Tim. 2:2). In these words, he recommends the condition of the Church to their protection and guardianship.
Duty to remove idols and images a "political law"
(Harmony of the Law Vol 3.9.1, entitled "Civil Supplements to the Second Commandment")
Exodus 23:24. Thou shalt utterly overthrow them. I allow indeed that these supplements would partly agree with, and be applicable to, the First Commandment; but since express mention is everywhere made in them of idols, this place seems to be better suited to them.
After Moses has taught what was necessary to be observed, he adds a political law about breaking down altars and overthrowing images, in order that the people may take the more diligent heed. From the words, when ye have come into the land “to possess it,” Augustine ( Aug. Serm. 62, Opp. Edit. Bened. T.v.p. 364.) sensibly infers, that there is no command for private individuals to destroy the instruments of idolatry; but that the people are armed and furnished with this authority to take the charge of regulating the public interests, when they have obtained possession of the land.
Duty of the Civil Magistrate to recognize God places them and for the purpose of carrying out His will
(Calvin, Sermons on Deuteronomy, Third Sermon Upon the First Chapter, 3/27/1555)
Last of all Moses says, I will set them over you to rule you. He shows that God had given him authority, and yet a man may see that he imparted it to that people, and showed by his doing, as we have seen before, that he challenged not to himself an inordinate power, but acknowledged that God had bound him to the common weal. So then, Moses has authority and knows well enough that God’s will was to prefer him above the rest of the people, and yet does not he abuse his right for all that, but refers all to the people. As if he should say, I will but only show the way how to guide, and in so doing I will take the pain to myself, as for the honor, I give it over to you. And the same mind ought to be in all good magistrates and governors of people, that they may be able to maintain the authority that is requisite: for even to that end also has God set them up.
Duty of the Civil Magistrate to enforce the First Commandment
(Calvin, Sermons on Deuteronomy, Fourth Sermon Upon the First Chapter, 4/11/1555)
Wherefore let us mark well this lesson wherein it is said that the judgment is God’s, that is to say, that the superiority which men have, in what degree so ever it be, is not to diminish God’s preeminence, but rather to maintain it. What then are the states of honor and all the dignities of the world? They are all means to bring to pass that God may reign over us, and to make all men to stoop to him, and to know him and obey him in all cases. So then, what ought kings, Emperors, and Magistrates to do? They ought to see that God be exalted and magnified as he is worthy, and that all their subjects do him homage, and they themselves must show them the way.
Duty of the Civil Magistrate to foster obedience to God and bear authority in God's name.
(Calvin, Sermons on Deuteronomy, Seventh Sermon Upon the Fifth Chapter, 6/26/1555)
Then if men and women have children: they must understand that there is no subjection due unto them, except they themselves be over ruled by God. Now then what is to be done? Let the father train up his child diligently in the fear of God, and begin himself to show him the way. Let the mother do the like, that God may have his honor both of great & small, old and young. Let magistrate endeavor to have God served and honored, & (as much as in them lies) maintain all things that may make thereto: and seeing he has done them that honor to make them worthy) to sit in the seat that is dedicated to his majesty, & to bear the sword that is consecrated unto him: let them show themselves to be his officers indeed. Seeing then that he has advanced them to such dignity, whereof they were not worthy: let them at the least show that they bear authority in his name, & let them refer the same unto him. After this manner ought princes to discharge their duties.
Then let us mark well, that diverse times the ground of rebellion & disobedience is this, that they which are in authority know not their own duty, namely that above all things they should find the means to have God honored, served, and obeyed. True it is that children, subjects and servants shall not be excused by that: but yet we see it is the just vengeance of God, & therefore so much the more ought we to be provoked to follow that which is told us, as well in this text as in all the holy Scripture, where this commandment is declared unto us. Then to be short, let us be well advised, that we discharge our duties every of us in his own calling and state. Let those to whom God has done the honor to give them the mace of Justice, & whom he has set in his seat, be well advised that they reign in his name, that they cause all men to serve and honor him, that they be as mirrors to give good example to their people, and that they hold their subjects in such good awe and order, as Gods name be blessed, and the mouths of all evil speakers be stopped.
Duty of the Civil Magistrate to prevent lewdness
(Calvin, Sermons on Deuteronomy, First Sermon Upon the Seventh Chapter, 8/1/1555)
For our Lord has ordained, not only that good causes should be maintained: but also that evil dealings should be corrected when they be found. And for the same purpose has he put his sword into the hands of princes, magistrates, and all other officers of justice, to the intent that lewdness should not be maintained in the world. Then is there no replying against this. And yet notwithstanding you shall have some that will complain of men as bloodsuckers, and as soon as any mention is made of the execution of justice, it is no better [with them] but cruelty. Let such folk get them to God, and go plead against him, to see if they can get the upper hand.
Duty of the Civil Magistrate to Promote the True Faith
(Calvin, Sermons on Deuteronomy, First Sermon Upon the Seventh Chapter, 8/1/1555)
God gives us leave to endeavor as much as is possible for us, to bring them back again which are out of the way of salvation. For as for the things that were spoken concerning the Amorites and the people that were their neighbors: they take not place so rigorously nowadays as though God gave us the sword in our hand, to flay all that were against us: but every of us must have an eye to his own state, and to the charge which God has committed to him. Magistrates are armed with the sword, to punish those whom God brings to their hands, and to put this doctrine in use.
Duty of the Civil Magistrate to enforce both tables of the law to promote fear of God and Right Religion
(Calvin, Sermons on Deuteronomy, Seventh Sermon Upon the Seventh Chapter, 8/14/1555)
Let us mark that this law is a part of the ancient order where to God meant to bind the Jews: and I have told you already that the ten verses have one everlasting rule, which God has given to continue to the world’s end. If we mind to have a doctrine that shall please and like God, our life must be comfortable to the law that is contained in the ten commandments: albeit, this present commandment served but for an order: like as when Christian magistrates make laws nowadays, are they against God’s word? No, but they do it in way of government and civil order, that their people maybe held the better in the fear of God and in the right religion.
Duty of the Civil Magistrate to withstand evil / that which offends God
(Calvin, Sermons on Deuteronomy, Sixth Sermon Upon the Ninth Chapter, 9/4/1555)
For he that lets evil slip, or prevents it not if he can, does give liberty to do evil. It is a saying even of the heathen, who to rebuke the negligence and coldness of magistrates and officers of justice, have alleged this proverb, That if he which ought to hinder evil do wink at it, it is all one as if he proclaimed leave and liberty to do evil by the sound of a trumpet, and he shall bear the blame of it before God. And indeed that proverb was commonly used, to do us to understand that God will not hold them excused, which have been so cold in executing their office. Now if the world condemns them: what will become of them, when they come before the heavenly judge? So then, Magistrates are here warned of their duty, namely that when they see any evil, they must withstand it. Although they be not armed with worldly force: yet must they rather forgo their lives, than yield in such sort as the mischief may get the mastery and the upper hand through their cowardliness. Let Lords of estate look well to themselves: for although men acquit them: yet shall they not be aquitted before GOD if they play the blinkered, and let naughtiness slip when they see God offended. If they see the right perverted, and do not manfully withstand it: they must yield account for it. And moreover, God will bring them to shame before the world, that they may feel the condemnation a forehand, which is prepared for them before him: and therefore let every man look nearly to himself.
Duty of the Church not to meddle in the administration of holy justice by the Civil Magistrate, all recognizing Christ's ultimate authority
(Calvin, Sermons on Deuteronomy, Second Sermon Upon the Eleventh Chapter, 9/23/1555)
I pray you what shall a man say, of those which have fought so manifestly against God after this fashion? For these things were not done of ignorance. Although they be so shameless as to say still, we have meant no such thing yet is their malice too apparent. For had no man spoken to them of it, or had no man pointed them as with his finger to the texts of the scripture, so as it might have been said, see here the will of God, there is no difficulty in the matter, it needs not any scanning as though there were any doubtfulness in it, see here the open text: [they might have had some colour for their pretence]. But seeing that things were so showed unto them, & yet they continued willful still: see you not that it was an open making of war against God? If Aaron have the high priesthood alone to himself, he shall have all superiority, & what shall we be? Even so stands the case with these men: to their seeming, all were marred on their side, if God should bear the sway. But God will bear the sway by this order, and we see it is no impeachment at all to the civil power which is a thing utterly distinct from it, neither can anything better maintain Magistrates in their sovereignty, forasmuch as the order of Gods Church is spiritual, so as it meddles not with the punishing of men’s bodies, nor with penalties, nor with imprisonments, nor with such other like things: but all is referred to the word & the sacraments. Seeing this is apparent does it not serve better for the establishment of Empires, kingdoms, & Lordships: than if there were nothing else to be had than a confuted tyranny, where nothing were reserved unto God & to our Lord Jesus Christ? And therefore when men strain themselves to the uttermost of their power to overthrow the order, do they not fall to spitting in the face of Jesus Christ to spite him withal?
Duty of the Civil Magistrate to enforce the First Commandment
(Calvin, Sermons on Deuteronomy, First Sermon Upon the Twelfth Chapter, 9/28/1555)
For if a man suffer his house to be defiled, and all things there to go to havoc: he shall be sure to make account thereof to God. Not that a man can hold his wife and servants continually tied to his sleeve to turn them to the Christian faith when he lifts: but my meaning is, that he must not suffer any superstition or idolatry. For why? Seeing that GOD has given him sovereignty in his own house; it behooves him to deal in such wise as GOD be honored there, and as no filthiness be mingled with the pure religion, but that all be rid quite and clean away. But as for Kings, princes, and Magistrates, which have power and authority, they must root out all superstition and idolatry. And seeing that GOD has armed them with the sword: it behooves them to use it in that behalf, so as they do not in any wise suffer or give leave, that there be any uncleanness to grieve GOD withal, or to abolish or deface his service.
Let those that are in estate of chief sovereignty, as kings, Princes and magistrates, let them I say consider, that since the Lord hath given them authority and power, if they suffer his service to be defaced; they shall be called to account for it.
Duty of the Civil Magistrate to enforce the First Table of the Law by the Sword and punish blasphemy and idolatry with death
(Calvin, Sermons on Deuteronomy, Second Sermon Upon the Thirteenth Chapter, 10/12/1555)
Then let us not think that this Law is a special Law for the Jews: but let us understand that GOD intended to deliver us a general rule, to which we must tire ourselves. Indeed it is alleged that when our Lord Jesus Christ came into the world, he advanced not his doctrine by the sword, but rather both he and his were persecuted, and therefore that the right way to maintain the true religion, is not to punish such as set up themselves against it: but rather to hold ourselves contented with the spiritual sword, and to use that in our fighting against Satan, so as our unholding of the truth, be always by sufferance and patience, if the world do persecute it. But let us see whether our Lord have excluded and banished Princes and Magistrates and Officers of Justice out of his flock, so as they may not be Christians. No surely. For when he speaks of the kingdom of our Lord Jesus Christ, he says expressly; You kings stand you in awe; and you Judges of the earth, humble you yourselves, and all of you kiss the son. Moreover, before he speak to private persons, he wills expressly that Kings, Judges, and Officers of Justice should do homage to our Lord Jesus Christ: then they be called to the knowledge of the Gospel. And indeed, according hereunto it is said in the Psalm, that kings shall come to submit themselves to him that was to be sent to be the redeemer. And again that they shall be as foster fathers to the Church, and that Queens shall give her suck; that is to say, that such as have the sword of justice in their hand, shall take Gods Church into their protection to maintain it in the pure doctrine, and in the same Religion that is set down in Gods word. Since it is so, it is to be concluded, not only that it is Lawful for all kings and Magistrates, to punish heretics and such as have perverted the pure truth: but also that they be bound to do it, and that they misbehave themselves towards GOD, if they suffer errors to roust without redress, and employ not their whole power to show a greater zeal in that behalf than in all other things. For is it reason that he which sits in the seat of Justice, should punish a thief for doing wrong but to the value of five shillings: and in the meanwhile let a traitor to GOD go unpunished? Gods name is thereby blasphemed, his truth which is his image is trampled under foot, and it is much more than if a man should rend some [prince's] coat of armor in pieces. In so doing the living image of GOD is scorned, and as it were spitted at, and the salvation of men’s souls hindered: and shall the Magistrates sit still at it like idols? They must punish a thief for the value of fifteen pence; and behold, this is such a traitor as goes about to confound heaven and earth together, and must the same go unpunished? What a dealing where that? Does not even nature teach what is to be done in this behalf? And as for those that say that we should let the evil weeds grow still, do they not show themselves to be grown out of kind like monsters, and that they be more intolerable than if they were stark mad? For it should seem that their meaning is to defy the whole order of nature, and men see that they not only speak against GOD, but also poison men’s souls, and betray themselves not to have one drop of settled discretion. Now then let us mark, that sith God has declared that in the reign of his son, even kings should be called to the knowledge of the truth, and become a part of his Church: It behooves them to give example to their people, and it is good reason that they should employ their whole power and authority to maintain the good doctrine, and to cause GOD to be honored and served, and to drive away all idolatry and superstition, and to see that it be not Lawful for any man to spew our blasphemies against GOD. That is the thing which we have to mark upon this place.But God meant to beat down all pride, that men might learn to challenge nothing to themselves. Notwithstanding howsoever the case stand, when the great ones are called to the service of God, then must they employ themselves in the things that I alleged out of Isaiah, David, and diverse other Psalms, belong to the reign of our Lord Jesus Christ, and to the state of the Christian Church. Therefore must we needs conclude, that our Lord will have Princes and magistrates to use the sword that is given them, o the maintenance of his honor, and of the unity of faith and good agreement; so as if any man raise up trouble or go about to sow darnel, he may be rooted out. But is not that punishment too rigorous? for some will well enough grant (as constrained thereunto) that it is good that heresies should be repressed: but that it were too great an extremity to proceed so far as to punish them with death. Yea, but (as I said afore) we must esteem God’s honor as it deserves. For if we would that deceivers should be reproved, so as they might not have their mouths open, and yet that they should not be utterly suppressed as were requisite: it were all one as if we should say, Indeed we ought to please God, but as for to put a man to death for blaspheming him, what a thing were that?
Duty of the Civil Magistrate to enforce the First Table of the Law and not only the Second Table
(Calvin, Sermons on Deuteronomy, Third Sermon Upon the Thirteenth Chapter, 10/16/1555)As for the Heathen, when they made laws for the observing of the manner of religion that was established among them; they had a good ground and foundation for the thing they did. For it is not enough for magistrates to make laws to repress robberies, murder, and violence; but they know also how it was meet that God should have the forehand. Now if nature taught them so much; what excuse will there be for us that profess Christianity, if we say it is enough for men to repress robberies, advowtries, murders, and other such violent and outrageous doing that tend to the hurt of private persons: and in the meanwhile make none account of God? What a dealing were that? The Heathen then had a good ground in that they knew that in a well ordered Common weal, religion ought to be observed, and that if any man attempted ought to the contrary, he was to be punished: in so much that it was a matter of life and death among them, and it was observed throughout all the world in all ages.