THE LORD’S PRAYER, POSTMILLENNIALISM, AND WESTMINSTER

The Lord Jesus Christ teaches us how to pray postmillennially.
The Lord’s prayer: (Mat 6:9-13)
This, then, is how you should pray:
Our Father in heaven, hallowed be your name,
{10} your kingdom come, your will be done on earth as it is in heaven.
{11} Give us today our daily bread.
{12} Forgive us our debts, as we also have forgiven our debtors.
{13} And lead us not into temptation, but deliver us from the evil one.’
Along with carrying out the Great Commission in the power of the Spirit, we are to pray that His kingdom comes and that his will be done on earth as it is in heaven. In other words we are to pray the kingdom in on the earth.
Note the words of Jesus to His disciples:
Then he said to his disciples, “The harvest is plentiful but the workers are few. {38} Ask (deomai) the Lord of the harvest, therefore, to send out workers into his harvest field.” (Mat 9:37-38 NIV)
The Westminster Confession of Faith and Catechisms (1647)
On the second petition of the Lord’s prayer it says:

In the second petition, (which is, Thy kingdom come,) acknowledging ourselves and all mankind to be by nature under the dominion of sin and Satan, we pray, that the kingdom of sin and Satan may be destroyed, the gospel propagated throughout the world, the Jews called, the fullness of the Gentiles brought in; the church furnished with all gospel-officers and ordinances, purged from corruption, countenanced and maintained by the civil magistrate: that the ordinances of Christ may be purely dispensed, and made effectual to the converting of those that are yet in their sins, and the confirming, comforting, and building up of those that are already converted: that Christ would rule in our hearts here, and hasten the time of his second coming, and our reigning with him forever: and that he would be pleased so to exercise the kingdom of his power in all the world, as may best conduce to those ends.

In an article on credal postmillennialism Andrew Sandlin says: “For while it is true that neither the creeds of early catholic orthodoxy nor the great confessions of the Reformation era contain a discussion of millennial terms (which, in any case, were not invented until last century), the eschatological notions of some of the latter documents cannot be understood equally well in any of the three main millennial frameworks (pre- , a- , and post-millennialism). A chief example is the Larger Catechism of the Westminster Confession of Faith, whose postmillennial eschatology seems implicit.”
For instance, Question 45 asks, How doth Christ execute the office of a king? The answer is

Christ executeth the office of a king, in calling out of the world a people to himself, and giving them officers, laws, and censures, by which he visibly governs them; in bestowing saving grace on his elect, rewarding them for their obedience, and correcting them for their sins; preserving and supporting them under all their temptations and sufferings, restraining and overcoming all their enemies, and powerfully ordering all things for his own glory, and their good; and also in taking vengeance on the rest, who know not God, and obey not the gospel.

There is no room in this answer for an increasingly evil world as posited by dispensationalism and much amillennialism. Lest the dispensationalist get the impression that the expressions “restraining and overcoming all their enemies” and “taking vengeance on the rest, who know not God, and obey not the gospel” refer exclusively to Christ’s exercise of kingly prerogatives after his second advent, he should note the answer to Question 42 declares that Christ “execute[s] the offices of prophet, priest, and, king of his church, in the estate both of his humiliation and [present] exaltation.” Moreover, lest the amillennialist deduce that these exercises of imperial rule pertain only to the increase of the church and not to the wider society, he should observe the texts the framers of the catechism offer as proof for their assertion: 1 Corinthians 15:25, Psalm 110:1, and, significantly, “the whole Psalm throughout.” Verses 5 and 6 of the Psalm state, “The Lord at thy right hand shall strike through kings in the day of his wrath. He shall judge among the heathen, he shall fill the places of the dead bodies; he shall wound the heads over many countries.” Although the language employed here is largely figurative and symbolical, the extent of Christ’s rule clearly transcends the church to include the Gentile nations and political rulers.
Further, the answer to query 54, How is Christ exalted in his sitting at the right hand of God?, includes the statement, “[He] doth gather and defend his church, and subdue her enemies,” employing again Psalm 110:1 and “the whole Psalm throughout” as Biblical proof. Obviously implied as enemies that Christ will subdue in his regal authority are the Gentiles and kings of the earth. This subdual, contra dispensational premillennialism, occurs in Christ’s present session, and contra much amillennialism, extends beyond the church to include the entire Gentile world.