Why is the tribulation not connected to the Body of Christ?
The tribulation is not connected to the Body of Christ because it belongs to the Old Testament program and is primarily for Israel. The Body of Christ, called out mainly from Gentiles, is insulated from God's dealings with Israel; it must be raptured before God brings the tribulation to Israel.
Les explains that after Israel rejected the Messiah, God raised up the Apostle Paul to call out the Body of Christ, primarily from among the Gentiles. Since this calling has nothing to do with the Old Testament program, it also has nothing to do with the tribulation, because the tribulation is tied to the Old Testament and primarily for the Jew. Les maintains that the Body of Christ is insulated from God's dealings with Israel either before or after, so it must be off the scene before God can pick up dealing with Israel. He teaches the Rapture because the Body of Christ has to be removed, and then God will yet bring in the tribulation to Israel. Removing the Church returns to the Old Testament economy of the coming Messiah, the tribulation, the King, and the Kingdom. Romans 11:25 is the triggering mechanism for Christ's coming for the Church, and there is no time element.