What would happen if every Jew became a Christian and the rapture took place?
If every Jew became a Christian and the rapture took place, no Jewish nation would remain in unbelief to fulfill prophecy. Israel must stay a nation in the land in unbelief for the seven-year Tribulation, for the 144,000—12,000 from each of the twelve tribes—and for Jeremiah 31's promise that Israel's national existence is tied to the sun, moon, and stars.
Les explains that God sovereignly watches over Israel like a hawk and keeps them intact as a nation. He recounts an Orthodox Jewish viewer who argued that you dare not evangelize all Jews, because then there would be no Jews left to fulfill prophecy. Les agrees: the nation of Israel has to be there in unbelief and in the land so God can consummate the seven years of tribulation. If every Jew were a Christian and a believer and the rapture took place, no one would be left to fulfill prophecy. There must be Jews remaining so the 144,000 can come from the twelve tribes, 12,000 from each tribe. Jeremiah 31 says the sun would fall out of its place and the sun, moon, and stars would cease to shine if Israel ceased to be a nation. Therefore Israel must stay, and believers should care for the fleshly needs of the Jew even today, contrary to rising anti-Semitism.