“Postmillennialism teaches that there is coming a time in earth history, continuous with the present and resultant from currently operating, God-ordained spiritual forces, in which the overwhelming majority of men and nations will voluntarily bow in salvation to the Lordship of Jesus Christ. This righteous submission to His gracious scepter will issue forth in widespread righteousness, peace, and prosperity. The eschatological theme in Scripture is a clearly discernible victory theme. It begins with the protoevangelium of Genesis 3:15 (which harmonizes with the creational purpose of God) and weaves its golden cord throughout Scripture all the way to Revelation 22. There is certainly the expectation of struggle in history. But it is a struggle that will triumphantly issue forth in victory rather than stalemate, defeat, or despair. The Seed of the Woman (Christ) will conquer the Seed of the Serpent (Satan) — in time and on earth. This is the fundamental truth of biblical eschatology.
Kenneth L. Jr. Gentry, He Shall Have Dominion: A Postmillennial Eschatology, n.d.