Why must Israel remain in unbelief and in the land?
Israel must remain in unbelief and in the land so God can consummate the seven-year tribulation and fulfill prophecy. If all Jews became believers and the rapture occurred, none would be left to fulfill prophecy, including the 144,000 from the twelve tribes. Jeremiah 31 says the sun, moon, and stars would cease if Israel ceased being a nation.
Les teaches that Israel has to stay in unbelief and in the land because God must consummate the seven years of tribulation. He illustrates this with an Orthodox Jewish viewer who told him you cannot evangelize all Jews, since no Jews would be left to fulfill prophecy. If every Jew became a Christian and a believer, and the rapture took place, no one would remain to fulfill prophecy. Les also points to the 144,000, with 12,000 from each of the twelve tribes, who must come from Israel. Jeremiah 31 says the sun, moon, and stars would cease to shine if Israel ceased being a nation, so they have to stay there. God watches over them like a hawk and keeps them intact as a nation, and Paul says believers should still care for the fleshly needs of the Jew, which opposes anti-Semitism.