The movement of Scripture seems to require a postmillennial eschatology.
Think about it. The Old Covenant moves from the Universal to the Particular after the fall. After the fall God’s salvation design is towards all men, but after the flood and after Babel that design is particularized to one people (Israel). From there the failure of Israel, like the failure of mankind prior to the flood, means an even more progressive reduction moving to “the remnant” and then finally culminating in this progressive reduction in the election of Jesus Christ to be God’s representative for the Redemption of His people. However, with the resurrection of Christ, we find the reversal of the previous progressive reduction to a progressive advance and broadening of redemption. What had been, prior to the arrival of Christ, a redemptive movement of the many to the one, with the resurrection the redemptive energy reverses and is now from the one to the many. We are still looking at election and representation, but the further salvific development unfolds so that from the center reached in the resurrection of Christ the way no longer leads from the many to the One but rather, as seen in the incorporating of the Nations, the movement of Redemption is progressively advancing from the one to the many. Consistently traced out this pattern and trajectory requires a belief in postmillennialism.
This hour-glass movement of Redemption (progressive reduction and narrowing to progressive advance and broadening) is most clearly articulated in Galatians 3:6 – 4:7. In that passage St. Paul begins with the promise to Abraham and his seed and reveals how ultimately the promise is to the Christ (3:16) who effectuates the ransom by His substitutionary death (4:5). This vicarious atonement results in the broadening of Redemption’s reach as all men and people may now become descendants of Abraham (3:26, 29) by faith alone in Christ alone. All may become “sons and heirs” (4:4-7) through baptism.
Maybe Warfield’s “Universal Postmillennialism” was correct?
In an interesting aside one can also see this double helix hourglass movement in the Christian measuring of time by way of metaphor. Before Christ (BC) the years are numbered in a progressive reduction. However, with the arrival of Christ (AD) the numbering of the years continues to climb progressively year by year. This becomes an excellent illustration for the way that the first Christians measured redemptive time. The center and focal point is Christ and with Christ time is reoriented with the Christ event.