A Christian is a follower of Jesus Christ, who believes that Jesus Christ, the only begotten Son of God and the incarnate image of God in the form of a human being. In the Christian view, a Believer is a Christian. Christians believe that Christ has paid for their sins on the cross with His blood and has given them eternal life in Him and that Christ rose from the dead three days later with the power of God, a sign of the first fruits of the resurrection of all the just in the last days. Christianity is diverse in its finer theological points. Many Christians believe that the Bible is the inerrant and infallible Word of God, though those that do often disagree on how it should be interpreted. Believers gather together in congregations called churches, and the overarching body of all believers is referred to collectively as The Church.
In the Left Behind books, all those who became believers prior to the events that took place in the first book were taken up in the Rapture along with babies, the unborn, and children that were too young to be held accountable for their actions. During the Tribulation, true Christian believers identified as "Tribulation saints", and were called "Judah-ites" after the scholar Tsion Ben-Judah, which was a tactic of the Antichrist to disassociate the dispensationalist beliefs of Ben-Judah from Christianity in general, marginalizing them. From the time just before the first Trumpet Judgment until the glorious appearing of Christ, believers were indicated and could spot each other by a cross mark that appears on their foreheads. A core group of believers formed both the Tribulation Force and the Young Tribulation Force to actively oppose the Antichrist Nicolae Carpathia and the activities of his Global Community. During the Millennium for "naturals", becoming a Christian before one's 100th birthday would allow that person to live through the Millennium and to enter into the "new heavens and new earth"; those that refused to become Christians before that time would die and go to Hell.