For Edwards, the two covenants were two phases or ways of performing the same one covenant. As Edwards put it early in his career, "The gospel was preached to the Jews under a veil." The process of conversion was the same for Jews in the Old Testament as for Christians in the New. They were "convinced so much of their wickedness that they trusted to nothing but the mere mercy of God." This included the antediluvians, and indeed all those who lived since "the beginning of the world." Even the rate of conversion was the same. There were wicked and godly then, and conversions were just as frequent then as in Edwards's day. Christ saved the Old Testament saints just like their cohorts in the New, and they believed in Christ, but under the name of the "angel of the Lord" or "messenger of the covenant." In fact, Christ appeared to Old Testament Jews; Moses saw his back parts on Mt. Sinai, and he appeared in human form to the seventy elders (Ex. 24:9-11) as well as to Joshua, Gideon, and Manoah. For that matter, every time God was said to have manifested himself to humans in a voice or otherwise tangible form, it was always through the second person of the Trinity.

Though the two covenants had two federal heads, Adam and Christ, and one was a "dead" way but the other "living," "in strictness of speech" they were not two but one. For they shared the same mediator, the same salvation (which means the same calling, justification, adoption, sanctification, and glory), and the same medium of salvation: the incarnation, suffering, righteousness, and intercession of Christ. The Holy Spirit was the same person applying Christ's redemption in both dispensations, and the method of obtaining salvation was the same—faith and repentance. The external means (the word of God and ordinances such as prayer and praise, sabbath, and sacraments) were not different. Nor were the benefits (God's Spirit by God's mere mercy and by a divine person—the angel of the Lord or Mediator) and future blessings. For both the condition was faith in the Son of God as Mediator, expressed with the same spirit of repentance and humility. This is why all parts of the Old Testament point to the future coming of Christ. In sum, the religion of the church of Israel is "essentially the same religion with that of the Christian church."

Edwards also determined that the Jews would return to their homeland. This would happen, he reasoned, because the prophecies of land being given to them had been only partially fulfilled. In the mid-18th century the majority of Jews were still living in the diaspora. It was also necessary for God to make them a "visible monument" of his grace and power at their return and then conversion. Canaan once again would be a spiritual center of the world. Although Israel would again be a distinct nation, Christians would have free access to Jerusalem because Jews would look on Christians as their brethren.

According to Arthur Hertzberg, this American linkage of Jewish conversion to the millennium was why "American intellectual anti-Semitism never became as virulent as its counterparts in Europe." Christians in Europe believed the End was in the indefinite future. But in America the End seemed near because of the influence of Puritan theology and its foregrounding of Israel, and according to these Puritans the End would not come without major changes in the fortunes of the Jews. So in the colonies, the Jewish question moved "to center stage."

So Edwards declined the invitation of the intellectual elites to minimize Christianity's debt to Judaism. If Christianity was the logical end of Judaism, its meaning could be found only through Judaism. The antitype was to be fully understood only by reference to its types. Hence tension in the Jewish-Christian relationship was a family quarrel. Edwards may have exercised a certain hubris by claiming that his Jewish brethren were less favored by their common Father, and indeed had been disowned. But he believed they would someday be reconciled to their divine Parent, and regain their status as children in full favor.

No evangelical thinker would ever again approach Edwards for subtlety and theological vision. But evangelicals continued his fascination with eschatology, and the Jewish role in it. In 1791 an evangelical Baptist minister, James Bicheno, published in London what was to be an influential and systematic treatment of prophetic themes, The Signs of the Times. Bicheno there argued that the restoration of Jews to Palestine must be imminent. For had not the Jews been given the "promised land" as their possession forever? Had not they received the Law, the revelation of God? And had not St. Paul insisted that in the end "all Israel will be saved" (Rom. 11.26)? Bicheno was the first to assert that it was in Britain's interest to use its foreign policy to promote the restoration of Israel, as a means of ushering in the millennium.

Bicheno was postmillennialist, as Edwards had been. His work inspired a raft of postmillennial English thinkers after the turn of the 19th century, well before the rise of premillennialism there in the 1820s and 1830s. Other English leaders such as Charles Simeon and William Wilberforce were also inspired by biblical prophecy to promote missions to Jews, but they were influenced more by Calvinist theology with its emphasis on God's election of a chosen people, and the philo-semitism of Lutheran pietists in German-speaking lands. All of these saw the significance of Jews to eschatology, but without concern for or belief in premillennialism.

In his Origins of Christian Zionism, Donald Lewis explains that it was a return to a closer and more literal reading of the Bible after the Reformation that gave all these Protestants a new interest in eschatology, and the role of the Jews within it. And in England especially, it was a shared Calvinism "that resonated with the idea of the divine 'election' of the Jews," not premillennialism or postmillennialism, that fired the imagination of the hordes of prophetically-minded English Protestants in the 19th century. Evangelicals in 19th-century England saw philo-semitism as their distinctive calling card, distinguishing them from Catholics who they claimed had persecuted Jews in the long history of Christianity, and from the Anglo-Catholicism of the Tractarian movement started by John Henry Newman. Both Catholics and Tractarians were asserting that they had the best historical claims to Christian faith; evangelicals used their philo-semitism to proclaim that their claims were even more ancient—going back to biblical Israel itself.

The most famous and powerful English philo-semite in the 19th century was Lord Ashley, the seventh earl of Shaftesbury (1801–85), ennobled in 1851. He "became the leading proponent of Christian Zionism in the nineteenth century and was the first politician of stature to prepare the way for Jews to establish a homeland in Palestine." His advocacy for a Jewish homeland was critical to the intellectual development behind the Balfour Declaration (1917).

What in particular inspired Shaftesbury? Lewis points to a number of influences:

1) Shaftesbury was a social reformer interested in the underdog, and he saw Jews as victims of historic Christian persecution. He shared a general British alarm at the persecution of Jews in the Damascus Blood Libel of 1840 and the mistreatment of Jews on the island of Rhodes as part of a general pattern in the declining Ottoman Empire.

2) He became an evangelical in the 1820s and most likely was influenced by postmillennialist Thomas Scott's Bible Commentary (1792), which popularized the idea of a Jewish return to the land.

3) He was ashamed that England was the first western nation to banish Jews, setting a terrible example to be repeated by France and Spain. Now England had the opportunity to be the first Gentile nation to cease to "tread down Jerusalem." This would lead not only to creating Jewish allies to the Empire all over the world, but it would also bring down the blessing of God on the Empire. Shaftesbury was convinced by Henry Hart Milman's History of the Jews (1829) that Jews are at the center of the story of the rise and fall of European nations: