Why do some Christians have trouble believing in a pre-trib rapture (or a rapture at all)? Maybe they don’t understand that Jesus paid our debt in full?
I think the biggest barrier to accepting the pre-trib rapture is the belief that the Church has to be purified by judgment to be made worthy to dwell with God. The idea that He would take us out of the way before He judges the world for its sins seems too good to be true. Even people who claim to be saved by grace have trouble believing this, especially when they look at the state of the Church today. However, to support this belief they have to interpret Scriptures in such a way as to make them say something the Lord never intended.
Also, many of them think that because of their own diligence the Lord will protect them throughout the time of judgment while judging other believers who haven’t lived a good Christian life. They apparently don’t realize that to God sin is not a matter of degree, and that there’s no one who could live a good enough life to escape judgment on his or her own merits. It’s a faith plus works equation that is not compatible with the doctrine of salvation by grace.
The only righteousness sufficient to protect us from judgment is the righteousness that comes from God through faith in Jesus Christ. This righteousness is given to all believers because from God’s perspective there’s no difference between us. We’re all sinners who fall short of the glory of God. By faith we are justified freely by God’s grace through the redemption that came by Christ Jesus (Romans 3:22-24).