There is no better time to refresh our memories about the “two kingdoms” doctrine than at election time in the United States, when American Protestantism often seems divided more by its political allegiances than its faith and practice.

In the aftershocks of the sacking of Rome by the pagans in 410 a.d., the great church father Augustine, bishop of Hippo, wrote his famous City of God. Jerome, another celebrated church father, had collapsed in despair: “What is to become of the church now that Rome has fallen?” No doubt as a patriot, Augustine felt the same wound, but as a Christian pastor he greeted the event as a providential opportunity: God had brought the mission field to the missionaries. The question was whether there were many “missionaries” left in an empire that had weakened the faith precisely to the extent that it had fused it with civil religion.  

Whether we face a similar possibility in our own civilization, we certainly stand in need of the wisdom that Augustine brought to the crisis. Like all great books, his City of God is interpreted rather differently by various schools. However, it is indisputable that it helped to create what came to be called the doctrine of the two kingdoms.  

According to Augustine, the distinction between the two cities — the city of God and the city of man — is grounded in the two loves: love of God and love of self. The former leads to genuine fellowship and a communion of mutual giving and receiving, while the latter engenders strife, war, and the desire to exercise domination over others.  

Ultimately, Augustine says, these two loves and two cities are themselves grounded in God’s eternal predestination. Although the city of man is destined to perish, God is both creating a new city (the church) from its ruins and preserving the old city by His common grace until ultimate peace and justice arrive with Christ’s return. In this era of common grace, God “sends rain on the just and on the unjust” and calls us to imitate His clemency (Matt. 5:43–48). So Christians have two callings: the high calling in Christ to belong to His body and the calling to the world as citizens, parents, children, friends, coworkers, and neighbors.    

Because God is still faithful to His creation, there is the possibility of an earthly city with its relative peace and justice; because God is faithful to His electing purposes, there is a church in all times and places that brings true peace and justice. He does this first of all by uniting sinners to Christ, and then one day by eradicating all strife from the earth at Christ’s return.  

Consequently, each city has its own polity, serving distinct ends through distinct means. Although some of its citizens are converted to citizenship in the city of God, the earthly city is always Babylon. Like Daniel, believers pray for the city, work in the city, contribute to the city’s general welfare, and even fight in its armies. However, they never forget that they are exiles and pilgrims. Babylon is never the promised land.  

The kingdom of God advances through the proclamation of the Gospel, not through the properly coercive powers of the state, although the church may take advantage of the relative peace that is possible in the earthly city (City of God, 19.26–27). These two cities we find “interwoven, as it were, in this present transitory world, and mingled with one another” (11.2). The good things that we do with non-Christian citizens to preserve and enlarge society really are good, but they are not ultimate goods. The earthly city will never be transformed into the city of God this side of Christ’s return in glory. A Christian would then approach politics not with the question as to how the world can best be saved, but how it can best be served in this time between the times.  

Throughout the Middle Ages, the national covenant that Israel made with God at Sinai was regularly invoked as an allegory for Christendom. Crusades against “the infidel” (often Muslims) were declared by popes with the promise of immediate entrance into paradise for martyrs. Kings fancied themselves as king David, leading the armies of the Lord in cleansing the Holy Land. The very idea of a Christian empire or a Christian nation was a serious confusion of these two cities. It was against this confusion of Christ’s kingdom with Israel’s theocracy that Luther and Calvin launched their retrieval of Augustine’s “two kingdoms.”  

Like Augustine, Luther emphasized the distinction between “things heavenly” and “things earthly,” righteousness before God and righteousness before fellow humans. On one hand, the Reformers were rejecting Rome’s confusion of Christ’s kingdom, which is extended by the proclamation of the Word, and earthly kingdoms. On the other hand, they were also opposing the Anabaptist movement, which regarded the earthly city as simply evil and unworthy of Christian involvement.  

Opposing what he called the “contrived empire” of Christendom, Calvin says that we must recognize that we are “under a two-fold government… so that we do not (as commonly happens) unwisely mingle these two, which have a completely different nature.” Just as the body and spirit are distinct without being intrinsically opposed, “Christ’s spiritual kingdom and the civil jurisdiction are things completely distinct. …Yet this distinction does not lead us to consider the whole nature of government a thing polluted, which has nothing to do with Christian men.” These two kingdoms are “distinct,” yet “they are not at variance” (Institutes of the Christian Religion, 4.20.1–2).  

Like Augustine, Calvin simultaneously affirms the natural order and its inability to generate an ultimate society because of sin. Bound to God as Creator in the covenant of creation, all human beings are heirs to a cultural mandate that they have transgressed. However, the cultural mandate is distinct from the Great Commission that belongs to the covenant of grace. The goal of common grace is not to perfect nature, but to restrain sin and animate civic virtues and arts, so that culture may fulfill its own important but limited, temporal, and secular ends, while God simultaneously pursues the redemptive aims of His everlasting city.  

Responding to the radical reformers’ insistence that a commonwealth is only legitimate if it is ordered by biblical law, Calvin declares, “How malicious and hateful toward public welfare would a man be who is offended by such diversity, which is perfectly adapted to maintain the observance of God’s law! For the statement of some, that the law of God given through Moses is dishonored when it is abrogated and new laws preferred to it, is utterly vain” (Institutes, 4.20.8, 14). After all, Calvin says, “It is a fact that the law of God which we call the moral law is nothing else than a testimony of natural law and of that conscience which God has engraved on the minds of men” (Institutes, 4.20.8, 14). Even unbelievers can rule justly and prudently, as Paul indicates even under the more pagan circumstances of his day (Rom. 13:1–7).  

When Jesus Christ arrived, He did not revive the Sinai theocracy as His contemporaries had hoped. Instead of driving out the Romans, He commanded love for our enemies. Gathering the new Israel — Jew and Gentile — around Himself, by His Spirit, through Word and sacrament, Jesus inaugurated the kingdom of grace that will be manifested one day as a kingdom of glory. In this time between His two comings the wheat grows together with the weeds, the sons of thunder are rebuked for calling down judgment here and now on those who reject their message, and the faithful gather regularly for the apostles’ teaching, fellowship, the breaking of the bread, and the prayers (Acts 2:42). Through its administration of Gospel preaching, baptism, the Supper, prayer, and discipline, the church is God’s new society inserted into the heart of the secular city as a witness to Christ and the age to come when He will be all in all.  

In our Christian circles in the United States today, we can discern a “Christendom” view, where some imagine America to be a Christian nation invested with a divine commission to bring freedom to the ends of the earth. Of course, Christians have an obligation both to proclaim the heavenly and everlasting freedom of the Gospel and the earthly and temporal freedom from injustice. But they are different. When we confuse them, we take the kingdom into our own hands, transforming it from a kingdom of grace into a kingdom of glory and power.  

We also recognize an opposite view, more characteristic of the Anabaptist perspective, as evangelist D. L. Moody asserted: “I look upon this world as a wrecked vessel. God has given me a lifeboat and said to me, ‘Moody, save all you can.’” In this view, improving the lot of our neighbors in the world is like polishing the brass on a sinking ship. Christians are often encouraged to focus almost exclusively on personal salvation (their own as well as that of others), unsure of the value of their secular vocations.    

But we need not choose between these two kingdoms. Citizens of both, we carry out our vocations in the church and the world in distinct ways through distinct means. We need not “Christianize” culture in order to appreciate it and participate in it with the gifts that God has given us as well as our non-Christian neighbors. Though called to be faithful in our callings until Christ returns, with Abraham, we are “looking forward to the city that has foundations, whose architect and builder is God” (Heb 11:10, HCSB).

Michael S. Horton is a Minister in the United Reformed Churfch.  He serves as a Professor of Systematic Theology and Apologetics at Westminster Seminary in California. This article is taken from the seminary blog and is used with permission