John Nelson Darby invented a hyper-grace theology (to be addressed in another essay). In this theology, the earthly salvation of Israel was based on the Law and the Gospel of the Kingdom whereas the Church was based on the Gospel of the grace of God (two different gospels) The promises to Israel are for earthly salvation, that is a particular destiny on this earth, a Kingdom order of the Millennial Age. The Church has a heavenly destiny and is a heavenly people. The Gospel of the Kingdom is the announcement of the Kingdom coming on the earth, that it is near, and Israel can embrace it leading to the Millennial Age. However, Israel rejected this offer, and the Kingdom was postponed. This postponement leads to an unforeseen dispensation, the Church Age, where the Gospel of the Grace of God is preached, not the Gospel of the Kingdom. This is the Gospel of salvation where heaven is offered to all who believe in Jesus as Savior. Jew and Gentile who are thus saved are part of the Church, a heavenly people, with a heavenly destiny and salvation. They are a third race. The Law has to do with Israel and its earthly promise and salvation. One can read about some of these distinctions in the little classic, Rightly Dividing the Word of Truth by C. I. Schofield. However, the more comprehensive presentation is in Louis Sperry Chafer’s Systematic Theology. I remember reading this in High School and just believed it because I believed my teachers at Word of Life Camps and Conferences in New York. It was not until my college years that this great edifice showed itself to be a house of cards. I did not realize how bizarre these binary categories were in the light of understanding the Bible in context, and also in understanding church historical interpretations. No one in Church History before Darby thought in such terms.
Once Darby had separated Israel and the Church in purpose and destiny, he taught that Israel and the Church had to be kept separate. Jews who come to faith are part of the Church and its destiny, part of the third race. They are not a part of the earthly Jewish people and their earthly salvation and promise. To make sure that that separation was complete, Darby taught that Israel was now placed on a preservation shelf awaiting that time when God would again take them off the shelf and make them his primary instrument for his working in the world. Then the remnant of Israel (Rev. 7) would again proclaim the Gospel of the Kingdom. This separation is crucial so as to not confuse law and grace and God’s distinct purposes for both; to not confuse the dispensation of the Church Age with the dispensations having to do with Israel; the Mosaic dispensation prevailing until Pentecost, the tribulation period and finally the Millennial Age where the Church rules as a heavenly Bride and Israel as an earthly people.
The Pre-tribulation rapture seemed the perfect solution to keep a strong separation between Israel and the Church. If the Church is taken off the earth, raptured, taken to heaven before the Tribulation, then after this, Israel can be God’s instrument on earth. The distinctions are maintained. The messiness of a joined purpose with Israel and the Church working together is overcome. The seven-year tribulation period is all about Israel and the nations, not about the Church. The Church is gone. She celebrates the Marriage Supper of the Lamb while God’s judgments are poured out on the earth and Israel experiences the Great Tribulation. Wherever Darby got this idea, the Irvingite prophetess, his own creative mind, or a demonic spirit, it was an amazing and novel answer to a non-problem which Darby thought up.
The Pre-tribulation rapture thus became a lynchpin of classic Dispensational thought.